diff --git a/packages/preview3-shim/test/filesystem.test.js b/packages/preview3-shim/test/filesystem.test.js
index 3f0a0f4d2..cdf4e4ed3 100644
--- a/packages/preview3-shim/test/filesystem.test.js
+++ b/packages/preview3-shim/test/filesystem.test.js
@@ -353,11 +353,12 @@ describe('Descriptor#setTimes and #setTimesAt', () => {
 
         await child.setTimes({ tag: 'now' }, { tag: 'now' });
         const after = await child.stat();
-        expect(after.dataAccessTimestamp.seconds).toBe(
-            before.dataAccessTimestamp.seconds + 5n
+
+        expect(after.dataAccessTimestamp.seconds).toBeGreaterThan(
+            before.dataAccessTimestamp.seconds
         );
-        expect(after.dataModificationTimestamp.seconds).toBe(
-            before.dataModificationTimestamp.seconds + 5n
+        expect(after.dataModificationTimestamp.seconds).toBeGreaterThan(
+            before.dataModificationTimestamp.seconds
         );
 
         child[Symbol.dispose]?.();
@@ -460,11 +461,11 @@ describe('Descriptor#setTimes and #setTimesAt', () => {
             { tag: 'now' }
         );
         const after = await rootDescriptor.statAt({ symlinkFollow: true }, sub);
-        expect(after.dataAccessTimestamp.seconds).toBe(
-            before.dataAccessTimestamp.seconds + 3n
+        expect(after.dataAccessTimestamp.seconds).toBeGreaterThan(
+            before.dataAccessTimestamp.seconds
         );
-        expect(after.dataModificationTimestamp.seconds).toBe(
-            before.dataModificationTimestamp.seconds + 3n
+        expect(after.dataModificationTimestamp.seconds).toBeGreaterThan(
+            before.dataModificationTimestamp.seconds
         );
 
         child[Symbol.dispose]?.();
@@ -485,11 +486,13 @@ describe('Descriptor#setTimes and #setTimesAt', () => {
         await dirDesc.setTimes({ tag: 'now' }, { tag: 'now' });
 
         const afterNow = await dirDesc.stat();
-        expect(afterNow.dataAccessTimestamp.seconds).toBe(
-            before.dataAccessTimestamp.seconds + 2n
+
+        // Check that timestamps have advanced
+        expect(afterNow.dataAccessTimestamp.seconds).toBeGreaterThan(
+            before.dataAccessTimestamp.seconds
         );
-        expect(afterNow.dataModificationTimestamp.seconds).toBe(
-            before.dataModificationTimestamp.seconds + 2n
+        expect(afterNow.dataModificationTimestamp.seconds).toBeGreaterThan(
+            before.dataModificationTimestamp.seconds
         );
 
         await dirDesc.setTimes(