diff --git a/app/multitenant/aws_collector.go b/app/multitenant/aws_collector.go
index 29a8bebd6..3a4a66144 100644
--- a/app/multitenant/aws_collector.go
+++ b/app/multitenant/aws_collector.go
@@ -274,11 +274,9 @@ func (c *awsCollector) reportKeysInRange(ctx context.Context, userid string, row
 	return result, nil
 }
 
-// getReportKeys returns the S3 for reports in the reporting window ending at timestamp.
-func (c *awsCollector) getReportKeys(ctx context.Context, timestamp time.Time) ([]string, error) {
+// getReportKeys returns the S3 for reports in the interval [start, end].
+func (c *awsCollector) getReportKeys(ctx context.Context, start, end time.Time) ([]string, error) {
 	var (
-		end      = timestamp
-		start    = end.Add(-c.cfg.Window)
 		rowStart = start.UnixNano() / time.Hour.Nanoseconds()
 		rowEnd   = end.UnixNano() / time.Hour.Nanoseconds()
 	)
@@ -351,7 +349,9 @@ func (c *awsCollector) getReports(ctx context.Context, reportKeys []string) ([]r
 func (c *awsCollector) Report(ctx context.Context, timestamp time.Time) (report.Report, error) {
 	span, ctx := opentracing.StartSpanFromContext(ctx, "awsCollector.Report")
 	defer span.Finish()
-	reportKeys, err := c.getReportKeys(ctx, timestamp)
+	end := timestamp
+	start := end.Add(-c.cfg.Window)
+	reportKeys, err := c.getReportKeys(ctx, start, end)
 	if err != nil {
 		return report.MakeReport(), err
 	}
@@ -366,7 +366,8 @@ func (c *awsCollector) Report(ctx context.Context, timestamp time.Time) (report.
 }
 
 func (c *awsCollector) HasReports(ctx context.Context, timestamp time.Time) (bool, error) {
-	reportKeys, err := c.getReportKeys(ctx, timestamp)
+	start := timestamp.Add(-c.cfg.Window)
+	reportKeys, err := c.getReportKeys(ctx, start, timestamp)
 	return len(reportKeys) > 0, err
 }