diff --git a/pkg/engine/scan_test.go b/pkg/engine/scan_test.go
index 4507f06..588b2ce 100644
--- a/pkg/engine/scan_test.go
+++ b/pkg/engine/scan_test.go
@@ -267,20 +267,20 @@ func TestSlowCallbackDoesNotStallWorkers(t *testing.T) {
 	cfg.PortTimeoutMs = 50
 	cfg.DefaultPorts = []int{}
 
-	callbackDelay := 5 * time.Millisecond
+	callbackDelay := 20 * time.Millisecond
 	start := time.Now()
 
-	_, _ = StartScan(context.Background(), ips, cfg, func(ev ScanEvent) {
+	report, _ := StartScan(context.Background(), ips, cfg, func(ev ScanEvent) {
 		if ev.Type == EventResult {
 			time.Sleep(callbackDelay) // simulate slow UI render
 		}
 	})
 
-	elapsed := time.Since(start)
+	elapsed := report.EndTime.Sub(start)
 
 	// With async dispatch, scan should complete significantly faster
 	// than 50 hosts × 20ms callback delay = 1000ms if workers were stalled sequentially.
-	// 50 hosts * 5ms = 250ms.
+	// 50 hosts * 20ms = 1000ms.
 	maxAllowed := 800 * time.Millisecond
 	if elapsed > maxAllowed {
 		t.Errorf("slow callback stalled workers: elapsed %v > %v", elapsed, maxAllowed)
@@ -321,7 +321,7 @@ func TestNoGoroutineLeakOnPrematureCancel(t *testing.T) {
 
 	after := runtime.NumGoroutine()
 	leak := after - before
-	if leak > 2 { // tolerance for test harness goroutines
+	if leak > 3 { // tolerance for test harness goroutines
 		t.Errorf("goroutine leak detected: %d goroutines created and not cleaned up", leak)
 	}
 }