diff --git a/Sense/scripts/t014-capacity.ps1 b/Sense/scripts/t014-capacity.ps1
index b1131bc..663dfff 100644
--- a/Sense/scripts/t014-capacity.ps1
+++ b/Sense/scripts/t014-capacity.ps1
@@ -802,9 +802,14 @@ try {
     $previousSampleAt = 0.0
     $initialInventory = Get-MediaInventory $script:productionAPIPort
     $samples = 0
+    $requiredSamples = [int][Math]::Ceiling($targetSeconds / $sampleSeconds)
     $maximumUnconverged = 0
-    while ($observation.Elapsed.TotalSeconds -lt $targetSeconds) {
-        Start-Sleep -Seconds $sampleSeconds
+    while ($samples -lt $requiredSamples) {
+        $nextSampleAt = ($samples + 1) * $sampleSeconds
+        $delayMilliseconds = [int][Math]::Ceiling(($nextSampleAt - $observation.Elapsed.TotalSeconds) * 1000)
+        if ($delayMilliseconds -gt 0) {
+            Start-Sleep -Milliseconds $delayMilliseconds
+        }
         Assert-Alive $sourceMedia
         Assert-Alive $productionMedia
         Assert-Alive $sense
@@ -848,7 +853,8 @@ try {
     $inboundMbps = if ($observationSeconds -gt 0) { ($inboundDelta * 8.0) / $observationSeconds / 1000000.0 } else { 0.0 }
     $databaseSizeBytes = [Int64](Get-PostgresScalar "SELECT pg_database_size('$databaseName')")
     $finalUnconverged = [int](Get-SenseMetric 'sense_reconcile_devices' '{state="unconverged"}')
-    if ($finalUnconverged -ne 0 -or $maximumUnconverged -ne 0 -or $samples -lt [Math]::Floor($targetSeconds / $sampleSeconds)) {
+    if ($observationSeconds -lt $targetSeconds -or $finalUnconverged -ne 0 -or
+        $maximumUnconverged -ne 0 -or $samples -lt $requiredSamples) {
         throw 'formal observation did not satisfy sampling and convergence requirements'
     }
 
diff --git a/tests/test_sense_capacity_contract.py b/tests/test_sense_capacity_contract.py
index dfba927..343eb18 100644
--- a/tests/test_sense_capacity_contract.py
+++ b/tests/test_sense_capacity_contract.py
@@ -32,6 +32,8 @@ class SenseCapacityContractTests(unittest.TestCase):
     def test_formal_window_and_functional_gates_are_fixed(self):
         self.assertRegex(self.script, r"\[int\]\$ObservationMinutes = 30")
         self.assertIn("$sampleSeconds = 10", self.script)
+        self.assertIn("$requiredSamples = [int][Math]::Ceiling($targetSeconds / $sampleSeconds)", self.script)
+        self.assertIn("$nextSampleAt = ($samples + 1) * $sampleSeconds", self.script)
         self.assertIn("formal_eligible = $ObservationMinutes -ge 30", self.script)
         self.assertIn("Wait-Convergence 'enabled'", self.script)
         self.assertIn("Wait-Convergence 'disabled'", self.script)