diff --git a/.github/workflows/phpunit.yml b/.github/workflows/phpunit.yml
index 6df58bf..da47ffb 100644
--- a/.github/workflows/phpunit.yml
+++ b/.github/workflows/phpunit.yml
@@ -20,7 +20,7 @@ jobs:
 
     strategy:
       matrix:
-        php-versions: [8.5]
+        php-versions: ['8.4', '8.5']
 
     steps:
       - name: Checkout
diff --git a/src/Service/IRPF.php b/src/Service/IRPF.php
index 549a029..b3ec723 100644
--- a/src/Service/IRPF.php
+++ b/src/Service/IRPF.php
@@ -141,9 +141,12 @@ private function usaDeducaoFavoravel(): bool
 
     private function calculaDeducaoFavoravel(float $inss, int $dependentes): float
     {
-        $simplificada = $this->calculaDeducaoSimplificada($inss);
+        $simplificada = $this->calculaDeducaoSimplificada();
         $tradicional = $this->calculaDeducaoTradicional($inss, $dependentes);
-        if ($simplificada <= $this->tabela['aliquotas'][0]['max'] * 0.25) {
+        // Compare both actual deductions, including dependents. The previous
+        // test compared the simplified value with its cap and ignored the
+        // total traditional deduction when INSS was below the cap.
+        if ($simplificada > $tradicional) {
             $this->tipoDeducao = 'simplificada';
             return $simplificada;
         }
@@ -156,13 +159,10 @@ public function getTipoDeducao(): string
         return $this->tipoDeducao;
     }
 
-    private function calculaDeducaoSimplificada(float $inss): float
+    private function calculaDeducaoSimplificada(): float
     {
-        $deducaoAliquotaPrimeiraFaixa = $this->tabela['aliquotas'][0]['max'] * 0.25;
-        if ($deducaoAliquotaPrimeiraFaixa > $inss) {
-            return $deducaoAliquotaPrimeiraFaixa;
-        }
-        return $inss;
+        // This option replaces (rather than adds to) legally allowed deductions.
+        return $this->tabela['aliquotas'][0]['max'] * 0.25;
     }
 
     private function calculaDeducaoTradicional(float $inss, int $dependentes): float
diff --git a/src/Service/modeloTabelaINSS.json b/src/Service/modeloTabelaINSS.json
index 40bdf4b..ab015c4 100644
--- a/src/Service/modeloTabelaINSS.json
+++ b/src/Service/modeloTabelaINSS.json
@@ -1,11 +1,11 @@
 {
     "2023": {
-        "0.11": 7087.22,
-        "0.2": 7087.22
+        "0.11": 7507.49,
+        "0.2": 7507.49
     },
     "2024": {
-        "0.11": 7087.22,
-        "0.2": 7087.22
+        "0.11": 7786.02,
+        "0.2": 7786.02
     },
     "2025": {
         "0.11": 8157.41,
diff --git a/src/Service/modeloTabelaIRPF.json b/src/Service/modeloTabelaIRPF.json
index 294aa9c..6c0d823 100644
--- a/src/Service/modeloTabelaIRPF.json
+++ b/src/Service/modeloTabelaIRPF.json
@@ -15,13 +15,13 @@
                     "min": 1993.99,
                     "max": 2826.65,
                     "aliquota": 0.075,
-                    "deducao": 142.80
+                    "deducao": 142.8
                 },
                 {
                     "min": 2826.66,
                     "max": 3751.05,
                     "aliquota": 0.15,
-                    "deducao": 354.80
+                    "deducao": 354.8
                 },
                 {
                     "min": 3751.06,
@@ -52,13 +52,13 @@
                     "min": 2112.01,
                     "max": 2826.65,
                     "aliquota": 0.075,
-                    "deducao": 158.40
+                    "deducao": 158.4
                 },
                 {
                     "min": 2826.66,
                     "max": 3751.05,
                     "aliquota": 0.15,
-                    "deducao": 370.40
+                    "deducao": 370.4
                 },
                 {
                     "min": 3751.06,
@@ -91,13 +91,13 @@
                     "min": 2112.01,
                     "max": 2826.65,
                     "aliquota": 0.075,
-                    "deducao": 158.40
+                    "deducao": 158.4
                 },
                 {
                     "min": 2826.66,
                     "max": 3751.05,
                     "aliquota": 0.15,
-                    "deducao": 370.40
+                    "deducao": 370.4
                 },
                 {
                     "min": 3751.06,
@@ -114,13 +114,13 @@
             ]
         },
         {
-            "mes_inicio": 1,
+            "mes_inicio": 2,
             "mes_fim": null,
             "deducao_por_dependente": 189.59,
             "aliquotas": [
                 {
                     "min": 0,
-                    "max": 2259.20,
+                    "max": 2259.2,
                     "aliquota": 0,
                     "deducao": 0
                 },
@@ -154,12 +154,12 @@
     "2025": [
         {
             "mes_inicio": 1,
-            "mes_fim": null,
+            "mes_fim": 4,
             "deducao_por_dependente": 189.59,
             "aliquotas": [
                 {
                     "min": 0,
-                    "max": 2259.20,
+                    "max": 2259.2,
                     "aliquota": 0,
                     "deducao": 0
                 },
@@ -188,6 +188,43 @@
                     "deducao": 896
                 }
             ]
+        },
+        {
+            "mes_inicio": 5,
+            "mes_fim": 12,
+            "deducao_por_dependente": 189.59,
+            "aliquotas": [
+                {
+                    "min": 0,
+                    "max": 2428.8,
+                    "aliquota": 0,
+                    "deducao": 0
+                },
+                {
+                    "min": 2428.81,
+                    "max": 2826.65,
+                    "aliquota": 0.075,
+                    "deducao": 182.16
+                },
+                {
+                    "min": 2826.66,
+                    "max": 3751.05,
+                    "aliquota": 0.15,
+                    "deducao": 394.16
+                },
+                {
+                    "min": 3751.06,
+                    "max": 4664.68,
+                    "aliquota": 0.225,
+                    "deducao": 675.49
+                },
+                {
+                    "min": 4664.69,
+                    "max": null,
+                    "aliquota": 0.275,
+                    "deducao": 908.73
+                }
+            ]
         }
     ],
     "2026": [
@@ -212,7 +249,7 @@
             "aliquotas": [
                 {
                     "min": 0,
-                    "max": 2428.80,
+                    "max": 2428.8,
                     "aliquota": 0,
                     "deducao": 0
                 },
diff --git a/tests/php/Service/INSSTest.php b/tests/php/Service/INSSTest.php
index 8ea43ba..2bda1a4 100644
--- a/tests/php/Service/INSSTest.php
+++ b/tests/php/Service/INSSTest.php
@@ -51,12 +51,12 @@ public static function providerCalcula(): array
             [7000, 2023, 0.2, 1400],
             [7087.16, 2023, 0.2, 1417.43],
             [7087.17, 2023, 0.2, 1417.43],
-            // Arredondamentos de centavos da base máxima começa aqui
+            // Valores abaixo do teto oficial de 2023 (R$ 7.507,49)
             [7087.18, 2023, 0.2, 1417.44],
             [7087.19, 2023, 0.2, 1417.44],
-            [7088, 2023, 0.2, 1417.44],
-            [8000, 2023, 0.2, 1417.44],
-            [100000, 2023, 0.2, 1417.44],
+            [7088, 2023, 0.2, 1417.60],
+            [8000, 2023, 0.2, 1501.50],
+            [100000, 2023, 0.2, 1501.50],
             [8475.54, 2026, 0.2, 1695.11],
             [8475.55, 2026, 0.2, 1695.11],
             [8475.56, 2026, 0.2, 1695.11],
diff --git a/tests/php/Service/IRPFRegressionTest.php b/tests/php/Service/IRPFRegressionTest.php
new file mode 100644
index 0000000..5f28626
--- /dev/null
+++ b/tests/php/Service/IRPFRegressionTest.php
@@ -0,0 +1,64 @@
+<?php
+
+declare(strict_types=1);
+
+use Impostos\Service\IRPF;
+use PHPUnit\Framework\TestCase;
+
+final class IRPFRegressionTest extends TestCase
+{
+    public function testHistoricalInssCapsMatchPublishedOfficialValues(): void
+    {
+        self::assertEqualsWithDelta(1501.498, (new \Impostos\Service\INSS(2023))->calcula(10000), 0.001);
+        self::assertEqualsWithDelta(1557.204, (new \Impostos\Service\INSS(2024))->calcula(10000), 0.001);
+        self::assertEqualsWithDelta(1695.11, (new \Impostos\Service\INSS(2026))->calcula(10000), 0.001);
+    }
+
+    public function testFebruary2024AppliesUpdatedTableNotJanuaryTable(): void
+    {
+        self::assertSame(0.075, (new IRPF(2024, 1))->getFaixa(2200.00)['aliquota']);
+        self::assertSame(0, (new IRPF(2024, 2))->getFaixa(2200.00)['aliquota']);
+    }
+
+    public function testSimplifiedDiscountDoesNotAddToSocialSecurityContributions(): void
+    {
+        $irpf = new IRPF(2026, 5);
+        $base = $irpf->calculaBase(4000.00, 400.00, 0);
+        self::assertEqualsWithDelta(3392.80, $base, 0.001);
+        self::assertSame('simplificada', $irpf->getTipoDeducao());
+    }
+
+    public function testJanuary2025RetainsOlderBracket(): void
+    {
+        self::assertSame(0.075, (new IRPF(2025, 1))->getFaixa(2300.00)['aliquota']);
+    }
+
+    public function testMay2025UsesUpdatedOfficialBracket(): void
+    {
+        self::assertSame(0, (new IRPF(2025, 5))->getFaixa(2300.00)['aliquota']);
+        self::assertEqualsWithDelta(182.16, (new IRPF(2025, 5))->getFaixa(2700.00)['deducao'], 0.00001);
+        self::assertEqualsWithDelta(607.20, 2428.80 * 0.25, 0.00001);
+    }
+
+    public function testTraditionalDeductionWinsWhenDependentsExceedSimplifiedDiscount(): void
+    {
+        $irpf = new IRPF(2026, 1);
+        self::assertEqualsWithDelta(4248.82, $irpf->calculaBase(5200.00, 572.00, 2), 0.00001);
+        self::assertSame('tradicional', $irpf->getTipoDeducao());
+    }
+
+    public function testSimplifiedDeductionWinsWithoutDependents(): void
+    {
+        $irpf = new IRPF(2026, 1);
+        self::assertEqualsWithDelta(4592.80, $irpf->calculaBase(5200.00, 572.00, 0), 0.00001);
+        self::assertSame('simplificada', $irpf->getTipoDeducao());
+    }
+
+    public function test2026ReductionMatchesFederalRevenueExample(): void
+    {
+        $irpf = new IRPF(2026, 1);
+        $base = $irpf->calculaBase(6000.00, 649.60, 0);
+        self::assertEqualsWithDelta(5350.40, $base, 0.00001);
+        self::assertEqualsWithDelta(382.88, round($irpf->calcula($base, 0), 2), 0.01);
+    }
+}
diff --git a/tests/php/Service/IRPFTest.php b/tests/php/Service/IRPFTest.php
index 4287aae..4c96e43 100644
--- a/tests/php/Service/IRPFTest.php
+++ b/tests/php/Service/IRPFTest.php
@@ -172,7 +172,7 @@ public static function providerCalculaBase(): array
             [2023, 5, 300, 0, 0, 'simplificada'],
             [2023, 5, 1000, 0, 472, 'simplificada'],
             [2023, 5, 3000, 0, 2400, 'tradicional'],
-            [2023, 5, 9000, 0, 7582.556, 'tradicional'],
+            [2023, 5, 9000, 0, 7498.502, 'tradicional'],
             [2023, 5, 2600, 0, 2072, 'simplificada'],
             [2023, 4, 2600, 0, 2080, 'tradicional'],
             [2026, 1, 300, 0, 0, 'simplificada'],
@@ -201,20 +201,20 @@ public static function providerCalculaImposto(): array
             # Sem dependente
             [2023, 5, 1000, 0, 0, 'simplificada'],
             [2023, 5, 3000, 0, 21.6, 'tradicional'],
-            [2023, 5, 9000, 0, 1200.24, 'tradicional'],
+            [2023, 5, 9000, 0, 1177.13, 'tradicional'],
             [2023, 5, 2600, 0, 0, 'simplificada'],
             [2023, 4, 2600, 0, 13.2, 'tradicional'],
             # Com 1 dependente
             [2023, 5, 1000, 1, 0, 'simplificada'],
             [2023, 5, 3000, 1, 7.38, 'tradicional'],
-            [2023, 5, 9000, 1, 1148.11, 'tradicional'],
-            [2023, 5, 2600, 1, 0, 'simplificada'],
+            [2023, 5, 9000, 1, 1124.99, 'tradicional'],
+            [2023, 5, 2600, 1, 0, 'tradicional'],
             [2023, 4, 2600, 1, 0, 'tradicional'],
             # Com 2 dependentes
-            [2023, 5, 1000, 2, 0, 'simplificada'],
+            [2023, 5, 1000, 2, 0, 'tradicional'],
             [2023, 5, 3000, 2, 0, 'tradicional'],
-            [2023, 5, 9000, 2, 1095.97, 'tradicional'],
-            [2023, 5, 2600, 2, 0, 'simplificada'],
+            [2023, 5, 9000, 2, 1072.85, 'tradicional'],
+            [2023, 5, 2600, 2, 0, 'tradicional'],
             [2023, 4, 2600, 2, 0, 'tradicional'],
             [2026, 1, 1000, 0, 0, 'simplificada'],
             [2026, 1, 3000, 0, 0, 'simplificada'],