diff --git a/CHANGELOG.md b/CHANGELOG.md
index 336f873..8a53d90 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - The canonical `@deepseek-ai/dsh-*` peer range now admits the `0.1.6-alpha.2` tuple (`|| >=0.1.6-0 <0.2.0`). The `peer-range` tripwire has been failing on `master` since that tuple was published, because semver's prerelease rule gives every new tuple its own clause; the three peers this package declares are re-pinned in the same commit, the lockfile's specifiers follow, and the `sync-peer-range` fixture's "higher-floor" example was raised above the new floor.
+- `scripts/sync-peer-range.mjs` no longer discards a real higher floor when the clause counts differ. `targetRange()` returned the canonical range as soon as `current.length !== canonical.length`, which was harmless only while canonical never changed length - and adding the `0.1.6-0` clause changed exactly that. A repo declaring `>=0.1.2-rc.1 <0.2.0 || >=0.1.5-rc.1 <0.2.0` (a genuinely higher 0.1.5 floor) was silently rewritten down to canonical's `>=0.1.5-alpha.1`; the same held for a single-clause `>=0.1.5-rc.1 <0.2.0`. Clauses now pair by `[major, minor, patch]` tuple when the counts differ, so the higher floor survives while the new clause is added, and a current clause in a tuple canonical does not carry is kept only when its floor is above every canonical floor. `test/sync-peer-range.test.mjs` covers the two-clause and single-clause cases, and the end-to-end fixture now exercises the merge instead of the raised-floor bypass.
 ## [0.1.9] - 2026-09-12
 
 ### Added
diff --git a/data/peer-range.json b/data/peer-range.json
index c3923c0..93a6f89 100644
--- a/data/peer-range.json
+++ b/data/peer-range.json
@@ -1,5 +1,5 @@
 {
   "canonicalRange": ">=0.1.2-rc.1 <0.2.0 || >=0.1.5-alpha.1 <0.2.0 || >=0.1.6-0 <0.2.0",
-  "updatedAt": "2026-09-19",
-  "note": "Canonical peerDependencies range for @deepseek-ai/dsh-* across the ecosystem. The OR form is required by semver's prerelease rule: a prerelease version only satisfies a comparator set when a comparator in the same [major, minor, patch] tuple carries a prerelease, so 0.1.5-rc.1 is NOT admitted by the bare '>=0.1.2-rc.1 <0.2.0'. Every new upstream prerelease tuple needs its own clause - run `node scripts/check-peer-range-latest.mjs` to detect a missing one (it reads the published dist-tags and prints the clause to append). Run `node scripts/sync-peer-range.mjs --dir <reposDir> --write` after updating this file to re-pin every repo, then let the shared Renovate preset open the update PRs."
+  "updatedAt": "2026-09-20",
+  "note": "Canonical peerDependencies range for @deepseek-ai/dsh-* across the ecosystem. The OR form is required by semver's prerelease rule: a prerelease version only satisfies a comparator set when a comparator in the same [major, minor, patch] tuple carries a prerelease, so 0.1.5-rc.1 is NOT admitted by the bare '>=0.1.2-rc.1 <0.2.0'. Every new upstream prerelease tuple needs its own clause - run `node scripts/check-peer-range-latest.mjs` to detect a missing one (it reads the published dist-tags and prints the clause to append). The third clause covers the 0.1.6 tuple with a '-0' floor, the same shape the tripwire suggests (never the bare '>=0.1.6' form): it admits every 0.1.6 prerelease including 0.1.6-alpha.2. Run `node scripts/sync-peer-range.mjs --dir <reposDir> --write` after updating this file to re-pin every repo, then let the shared Renovate preset open the update PRs."
 }
diff --git a/scripts/sync-peer-range.mjs b/scripts/sync-peer-range.mjs
index 208557c..ad40df9 100644
--- a/scripts/sync-peer-range.mjs
+++ b/scripts/sync-peer-range.mjs
@@ -130,21 +130,49 @@ export function rangeStatus(current, canonical) {
   return maxOf(cur, 'floor') >= maxOf(can, 'floor') ? 'ok-higher' : 'drift-low'
 }
 
+/** `0.1.6-0` / `0.1.5-alpha.1` -> `0.1.6` / `0.1.5` (the [major, minor, patch] tuple). */
+function floorTuple(floor) {
+  return String(floor).split('-')[0]
+}
+
 /**
  * Target range for a drifting key: the canonical clause set, keeping the
- * higher of each pairwise floor. Clause counts that differ fall back to the
- * canonical range as-is (a clause was added or removed upstream).
+ * higher of each floor. Equal-length sets merge pairwise by position; when
+ * the counts differ, clauses pair up by [major, minor, patch] tuple instead,
+ * so a repo that carries a real higher floor in one tuple (e.g.
+ * `>=0.1.5-rc.1` where canonical says `>=0.1.5-alpha.1`) keeps it even when
+ * canonical gains a clause - the old `length !== length` early return
+ * silently dropped such floors back to canonical. A current clause whose
+ * tuple canonical does not carry is preserved only when its floor is above
+ * every canonical floor (a genuinely higher requirement); anything below is
+ * drift-low and is raised to the canonical clause set.
  */
 export function targetRange(current, canonical) {
   const cur = parseRangeSet(current)
   const can = parseRangeSet(canonical)
-  if (!cur || !can || cur.length !== can.length) return canonical
-  return formatRangeSet(
-    can.map((c, i) => ({
-      floor: cur[i].floor > c.floor ? cur[i].floor : c.floor,
-      upper: c.upper,
-    })),
-  )
+  if (!cur || !can) return canonical
+  if (cur.length === can.length) {
+    return formatRangeSet(
+      can.map((c, i) => ({
+        floor: cur[i].floor > c.floor ? cur[i].floor : c.floor,
+        upper: c.upper,
+      })),
+    )
+  }
+  const curByTuple = new Map(cur.map((c) => [floorTuple(c.floor), c]))
+  const merged = can.map((c) => {
+    const pair = curByTuple.get(floorTuple(c.floor))
+    if (pair) curByTuple.delete(floorTuple(c.floor))
+    return pair
+      ? { floor: pair.floor > c.floor ? pair.floor : c.floor, upper: c.upper }
+      : c
+  })
+  const maxFloor = maxOf(can, 'floor')
+  const upper = maxOf(can, 'upper')
+  for (const extra of curByTuple.values()) {
+    if (extra.floor > maxFloor) merged.push({ floor: extra.floor, upper })
+  }
+  return formatRangeSet(merged)
 }
 
 /**
diff --git a/test/check-peer-range-latest.test.mjs b/test/check-peer-range-latest.test.mjs
index e4614f5..f40f7a3 100644
--- a/test/check-peer-range-latest.test.mjs
+++ b/test/check-peer-range-latest.test.mjs
@@ -8,7 +8,7 @@ import {
   suggestedClause,
 } from '../scripts/check-peer-range-latest.mjs'
 
-const CANONICAL = '>=0.1.2-rc.1 <0.2.0 || >=0.1.5-alpha.1 <0.2.0'
+const CANONICAL = '>=0.1.2-rc.1 <0.2.0 || >=0.1.5-alpha.1 <0.2.0 || >=0.1.6-0 <0.2.0'
 
 describe('parseVersion / compareVersions', () => {
   it('parses release and prerelease versions', () => {
@@ -54,8 +54,14 @@ describe('satisfiesRange', () => {
     expect(satisfiesRange('0.1.6', CANONICAL)).toBe(true)
   })
 
+  it('admits the 0.1.6 tuple through its own -0 clause', () => {
+    expect(satisfiesRange('0.1.6-rc.1', CANONICAL)).toBe(true)
+    expect(satisfiesRange('0.1.6-alpha.0', CANONICAL)).toBe(true)
+    expect(satisfiesRange('0.1.6-alpha.2', CANONICAL)).toBe(true)
+  })
+
   it('does NOT admit a future prerelease tuple (the reason the tripwire exists)', () => {
-    expect(satisfiesRange('0.1.6-rc.1', CANONICAL)).toBe(false)
+    expect(satisfiesRange('0.1.7-rc.1', CANONICAL)).toBe(false)
   })
 
   it('rejects unparseable input instead of throwing', () => {
diff --git a/test/sync-peer-range.test.mjs b/test/sync-peer-range.test.mjs
index fd176a7..62e037e 100644
--- a/test/sync-peer-range.test.mjs
+++ b/test/sync-peer-range.test.mjs
@@ -74,6 +74,21 @@ describe('OR-form range sets', () => {
     expect(targetRange('>=0.1.2-rc.1 <0.2.0', OR)).toBe(OR)
     expect(targetRange('>=0.1.1-rc.2 <0.2.0', OR)).toBe(OR)
   })
+
+  it('merges per-tuple floors when clause counts differ (R3 fix)', () => {
+    const THREE = '>=0.1.2-rc.1 <0.2.0 || >=0.1.5-alpha.1 <0.2.0 || >=0.1.6-0 <0.2.0'
+    // the old two-clause canonical gains the new tuple clause
+    expect(targetRange('>=0.1.2-rc.1 <0.2.0 || >=0.1.5-alpha.1 <0.2.0', THREE)).toBe(THREE)
+    // a current two-clause range with a real higher floor keeps it while the
+    // third clause is added - the old early return silently lost the rc.1
+    expect(targetRange('>=0.1.2-rc.1 <0.2.0 || >=0.1.5-rc.1 <0.2.0', THREE)).toBe(
+      '>=0.1.2-rc.1 <0.2.0 || >=0.1.5-rc.1 <0.2.0 || >=0.1.6-0 <0.2.0',
+    )
+    // even a single-clause higher floor is preserved while the set is raised
+    expect(targetRange('>=0.1.5-rc.1 <0.2.0', THREE)).toBe(
+      '>=0.1.2-rc.1 <0.2.0 || >=0.1.5-rc.1 <0.2.0 || >=0.1.6-0 <0.2.0',
+    )
+  })
 })
 
 describe('rewritePeerRange', () => {
@@ -139,13 +154,13 @@ describe('currentPeerRanges', () => {
 })
 
 describe('CLI end-to-end', () => {
-  it('reports drift without --write and rewrites only drifting keys with --write', async () => {
+  it('reports drift without --write; --write adds the third clause and keeps a higher floor', async () => {
     const canonical = JSON.parse(
       await readFile(resolve(import.meta.dirname, '..', 'data', 'peer-range.json'), 'utf8'),
     ).canonicalRange
-    // above every canonical floor: a real per-package requirement, left alone
-    // (raised together with canonicalRange's newest tuple, 2026-09-19)
-    const highFloor = '>=0.1.6-rc.1 <0.2.0'
+    // two-clause current with a real higher floor in the 0.1.5 tuple: the
+    // rewrite must preserve it while adding the third canonical clause
+    const highFloor = '>=0.1.2-rc.1 <0.2.0 || >=0.1.5-rc.1 <0.2.0'
     const repoDir = join(dir, 'cli-repo')
     await mkdir(repoDir, { recursive: true })
     const pkg = join(repoDir, 'package.json')
@@ -158,11 +173,13 @@ describe('CLI end-to-end', () => {
     expect(report).toContain('cli-repo\tdrift')
     expect(report).toContain('@deepseek-ai/dsh-session: drift-low')
     const rewrite = execFileSync(process.execPath, [script, '--dir', dir, '--write'], { encoding: 'utf8' })
-    expect(rewrite).toContain('rewritten (1 keys)')
+    expect(rewrite).toContain('rewritten (2 keys)')
     const after = await readFile(pkg, 'utf8')
     expect(after).toContain(`"@deepseek-ai/dsh-session": "${canonical}"`)
-    // higher-floor key untouched by the rewrite
-    expect(after).toContain(`"@deepseek-ai/dsh-projection": "${highFloor}"`)
+    // the higher 0.1.5 floor survives the rewrite and the third clause is added
+    expect(after).toContain(
+      `"@deepseek-ai/dsh-projection": ">=0.1.2-rc.1 <0.2.0 || >=0.1.5-rc.1 <0.2.0 || >=0.1.6-0 <0.2.0"`,
+    )
     const second = execFileSync(process.execPath, [script, '--dir', dir], { encoding: 'utf8' })
     expect(second).toContain('cli-repo\tok (1 higher-floor)')
   })