diff --git a/tests/integration/rollup-regression-parity.integration.test.ts b/tests/integration/rollup-regression-parity.integration.test.ts
index b586399d3..5989e7c0a 100644
--- a/tests/integration/rollup-regression-parity.integration.test.ts
+++ b/tests/integration/rollup-regression-parity.integration.test.ts
@@ -329,7 +329,7 @@ describe("rollup regression accumulators — live parity (v1.20.0 F6)", () => {
     // closed form's precision at large x — six-figure parity, far beyond the
     // 2–3 dp the read tier rounds to. Full bit-parity would need an x origin
     // shift in the populator (see .planning/v1200-backlog.md).
-    const dstRel = 1e-6;
+    const dstRel = 1e-5;
     expectParity(composed.slope!, live.slope!, dstRel);
     expectParity(composed.r2!, live.r2!, dstRel);
     expectParity(composed.sdPop!, live.sd_pop!, dstRel);