diff --git a/pcu/PCU_Tests.ttcn b/pcu/PCU_Tests.ttcn
index 5f60cef..187e2f1 100644
--- a/pcu/PCU_Tests.ttcn
+++ b/pcu/PCU_Tests.ttcn
@@ -1365,12 +1365,11 @@
 		if (rx_usf == ms.ul_tbf.usf[valueof(nr.ts_nr)]) {
 			log("PCU requests our USF ", rx_usf, ", n3101=", n3101);
 			n3101 := n3101 + 1;
-			//"if (n3101 > N3101_MAX) {" -> start timer T3169
-			if (n3101 > N3101_MAX) {
-				setverdict(fail, "Reached ", n3101, " > ", N3101_MAX, " (N3101_MAX) and PCU still sends us USFs");
+			if (n3101 > N3101_MAX + 1) { //+1: DL<->UL FN offset
+				setverdict(fail, "Reached ", n3101, " > ", N3101_MAX + 1, " (N3101_MAX+1) and PCU still sends us USFs");
 				f_shutdown(__BFILE__, __LINE__);
 			}
-		} else if (rx_usf == USF_UNUSED and n3101 == N3101_MAX) {
+		} else if (rx_usf == USF_UNUSED and n3101 == N3101_MAX + 1) {
 			/* If we already received USFs for us and we don't receive them anymore, that means the TBF entered T3169 */
 			log("PCU stopped requesting USF ", ms.ul_tbf.usf[valueof(nr.ts_nr)]);
 			if (not T_3169.running) {