diff --git a/dpppt-backend-sdk/dpppt-backend-sdk-data/src/main/java/org/dpppt/backend/sdk/data/gaen/JDBCGAENDataServiceImpl.java b/dpppt-backend-sdk/dpppt-backend-sdk-data/src/main/java/org/dpppt/backend/sdk/data/gaen/JDBCGAENDataServiceImpl.java
index 84223bbe..fb6b47cb 100644
--- a/dpppt-backend-sdk/dpppt-backend-sdk-data/src/main/java/org/dpppt/backend/sdk/data/gaen/JDBCGAENDataServiceImpl.java
+++ b/dpppt-backend-sdk/dpppt-backend-sdk-data/src/main/java/org/dpppt/backend/sdk/data/gaen/JDBCGAENDataServiceImpl.java
@@ -63,7 +63,12 @@ public void upsertExposeesDelayed(List<GaenKey> gaenKeys, OffsetDateTime delayed
 		}
 		var parameterList = new ArrayList<MapSqlParameterSource>();
 		var nowMillis = System.currentTimeMillis();
-		//if delayedReceivedAt is supplied use it
+		// if delayedReceivedAt is supplied use it
+		// else we calculate the last moment of the  current  bucket like this:
+		// currentBucketNumber = Floor(now/releaseBucketDuration)
+		// nextBucketNumber = currentBucketNumber + 1
+		// nextBucket = nextBucketNumber * releaseBucketDuration
+		// Since we have millisecond precision => lastMomentOfCurrentBucket = nextBucket - 1
 		var receivedAt = delayedReceivedAt == null? (nowMillis/releaseBucketDuration.toMillis() + 1) * releaseBucketDuration.toMillis() - 1 : delayedReceivedAt.toInstant().toEpochMilli(); 
 		for (var gaenKey : gaenKeys) {
 			MapSqlParameterSource params = new MapSqlParameterSource();
diff --git a/dpppt-backend-sdk/dpppt-backend-sdk-ws/src/main/java/org/dpppt/backend/sdk/ws/controller/GaenController.java b/dpppt-backend-sdk/dpppt-backend-sdk-ws/src/main/java/org/dpppt/backend/sdk/ws/controller/GaenController.java
index 14889b8a..0e9bccdd 100644
--- a/dpppt-backend-sdk/dpppt-backend-sdk-ws/src/main/java/org/dpppt/backend/sdk/ws/controller/GaenController.java
+++ b/dpppt-backend-sdk/dpppt-backend-sdk-ws/src/main/java/org/dpppt/backend/sdk/ws/controller/GaenController.java
@@ -150,8 +150,9 @@ public GaenController(GAENDataService dataService, FakeKeyService fakeKeyService
 			}
 			
 			if(delayTodaysKeys) {
-				// Additionally to delaying keys this feature also make sure rolling period is always set to 144 
-				// to make sure iOS 13.5.x does not ignore the TEK.
+				// Additionally to delaying keys this feature also makes sure rolling period is always set to 144 
+				// to make sure iOS 13.5.x does not ignore the TEK. The calculations of the RPIs should still be true,
+				// though more keys might be checked.
 				key.setRollingPeriod(GaenKey.GaenKeyDefaultRollingPeriod);
 
 				var rollingStartNumberDuration = Duration.of(key.getRollingStartNumber(), GaenUnit.TenMinutes).toMillis();