diff --git a/Sources/CodexLimits/UsageIntelligenceEngine.swift b/Sources/CodexLimits/UsageIntelligenceEngine.swift
index 92c7099..2410150 100644
--- a/Sources/CodexLimits/UsageIntelligenceEngine.swift
+++ b/Sources/CodexLimits/UsageIntelligenceEngine.swift
@@ -745,9 +745,13 @@ private enum RecentMovementBreak {
 
 enum UsageIntelligenceEngine {
     static func evaluate(_ input: UsageIntelligenceInput) -> UsageReaderSnapshot {
+        let samples = UsageHistoryPolicy.aligningWindowResets(
+            input.samples,
+            currentReset: input.account?.mainLimit?.window.resetsAt
+        )
         let currentSamples = input.account.flatMap { account in
             account.mainLimit.map { weeklyLimit in
-            input.samples
+            samples
                 .filter { sample in
                     sample.resetsAt == weeklyLimit.window.resetsAt
                         && sample.observedAt >= weeklyLimit.window.startsAt
@@ -792,7 +796,7 @@ enum UsageIntelligenceEngine {
         )
         let recentMovement = recentAccountMovement(
             account: input.account,
-            samples: input.samples,
+            samples: samples,
             sourceState: input.sourceState,
             now: input.now,
             accountEpochStartedAt: input.accountEpochStartedAt
@@ -802,7 +806,7 @@ enum UsageIntelligenceEngine {
                   let weeklyLimit = account.mainLimit else { return nil }
             return ForecastEngine.evaluate(
                 window: weeklyLimit.window,
-                samples: input.samples,
+                samples: samples,
                 tokenHistory: account.tokenHistory,
                 safetyBuffer: input.safetyBuffer,
                 now: input.now,
@@ -849,7 +853,7 @@ enum UsageIntelligenceEngine {
         }
         let chart = chart(
             account: input.account,
-            samples: input.samples,
+            samples: samples,
             forecast: forecast,
             recentMovement: recentMovement.movement,
             sourceState: input.sourceState,
@@ -888,7 +892,7 @@ enum UsageIntelligenceEngine {
         let accountTokenActivity = if let selectedTokenRange {
             selectedRangeAccountTokenActivity(
                 account: input.account,
-                samples: input.samples,
+                samples: samples,
                 range: selectedTokenRange,
                 now: input.now,
                 accountPartitionID: input.accountPartitionID,
@@ -979,7 +983,7 @@ enum UsageIntelligenceEngine {
             let evidence: WeeklyUsageEvidenceSet
             if let reusableLocalHistory,
                reusableLocalHistory.matches(
-                   samples: input.samples,
+                   samples: samples,
                    observation: input.localActivityObservation,
                    accountPartitionID: partitionID,
                    limitID: weekly.limitId,
@@ -990,7 +994,7 @@ enum UsageIntelligenceEngine {
                 reusedWeeklyEvidence = true
             } else {
                 evidence = WeeklyUsageEvidenceBuilder.build(
-                    samples: input.samples,
+                    samples: samples,
                     localFacts: input.localActivityHistoryFacts,
                     localObservation: input.localActivityObservation,
                     accountPartitionID: partitionID,
@@ -1068,7 +1072,7 @@ enum UsageIntelligenceEngine {
                   let weekly = input.account?.mainLimit {
             localHistoryCache = LocalHistoryAggregateCache(
                 factIndex: localHistoryFactIndex,
-                samples: input.samples,
+                samples: samples,
                 observation: input.localActivityObservation,
                 accountPartitionID: partitionID,
                 limitID: weekly.limitId,
diff --git a/Sources/CodexLimits/UsageModels.swift b/Sources/CodexLimits/UsageModels.swift
index 79e7789..09bcc5d 100644
--- a/Sources/CodexLimits/UsageModels.swift
+++ b/Sources/CodexLimits/UsageModels.swift
@@ -148,6 +148,33 @@ enum UsageHistoryPolicy {
     static let tightBoundary: TimeInterval = 15 * 60
     static let maximumComparableGap: TimeInterval = 30 * 60
 
+    static func aligningWindowResets(
+        _ samples: [UsageSample],
+        currentReset: Date?
+    ) -> [UsageSample] {
+        var anchors = currentReset.map { [$0] } ?? []
+        var aligned: [Date: Date] = [:]
+        for sample in samples.sorted(by: { $0.observedAt > $1.observedAt })
+        where aligned[sample.resetsAt] == nil {
+            let anchor = anchors.first {
+                abs($0.timeIntervalSince(sample.resetsAt)) <= tightBoundary
+            } ?? sample.resetsAt
+            aligned[sample.resetsAt] = anchor
+            if anchor == sample.resetsAt { anchors.append(anchor) }
+        }
+        return samples.map { sample in
+            guard let reset = aligned[sample.resetsAt],
+                  reset != sample.resetsAt else { return sample }
+            return UsageSample(
+                observedAt: sample.observedAt,
+                remainingPercent: sample.remainingPercent,
+                resetsAt: reset,
+                lifetimeTokens: sample.lifetimeTokens,
+                comparisonBreak: sample.comparisonBreak
+            )
+        }
+    }
+
     static func segments(
         _ samples: [UsageSample]
     ) -> [[UsageSample]] {
diff --git a/Tests/CodexLimitsTests/UsageIntelligenceEngineTests.swift b/Tests/CodexLimitsTests/UsageIntelligenceEngineTests.swift
index 7b2790c..2068827 100644
--- a/Tests/CodexLimitsTests/UsageIntelligenceEngineTests.swift
+++ b/Tests/CodexLimitsTests/UsageIntelligenceEngineTests.swift
@@ -2394,6 +2394,36 @@ final class UsageIntelligenceEngineTests: XCTestCase {
         )
     }
 
+    func testResetTimeJitterDoesNotCreateASecondAllowanceWindow() {
+        let now = Date(timeIntervalSince1970: 6_400_000)
+        let account = makeSnapshot(remaining: 34, fetchedAt: now)
+        let reset = account.mainLimit!.window.resetsAt
+        let reader = UsageIntelligenceEngine.evaluate(
+            UsageIntelligenceInput(
+                account: account,
+                samples: [
+                    UsageSample(
+                        observedAt: now.addingTimeInterval(-3 * 86_400),
+                        remainingPercent: 70,
+                        resetsAt: reset.addingTimeInterval(1)
+                    ),
+                    UsageSample(
+                        observedAt: now.addingTimeInterval(-60),
+                        remainingPercent: 34,
+                        resetsAt: reset.addingTimeInterval(1)
+                    )
+                ],
+                safetyBuffer: 3,
+                sourceState: .available,
+                now: now,
+                previousStatus: nil
+            )
+        )
+
+        XCTAssertEqual(reader.chart.allowanceWindows.count, 1)
+        XCTAssertEqual(reader.chart.observed.count, 3)
+    }
+
     func testAccountEpochDoesNotHideStoredChartPoints() {
         let now = Date(timeIntervalSince1970: 6_400_000)
         let account = makeSnapshot(remaining: 70, fetchedAt: now)