diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index 8944447..de35e23 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -6889,7 +6889,6 @@
 	var bitstring full_mask := f_pad_bit(''B, 1024, '0'B);
 	var bitstring slot_mask := f_pad_bit(''B, 1024, '0'B);
 	var bitstring ma_mask := ''B;
-	var integer ma_mask_len := 0;
 
 	/* Compose the full bit-mask (all channels, up to 1024 entries) */
 	for (var integer i := 0; i < lengthof(fhp); i := i + 1) {
@@ -6913,15 +6912,13 @@
 		/* FIXME: ma_mask := ma_mask & slot_mask[i]; // triggers a bug in TITAN */
 		if (slot_mask[i] == '1'B) {
 			ma_mask := ma_mask & '1'B;
-			ma_mask_len := lengthof(ma_mask);
 		} else {
 			ma_mask := ma_mask & '0'B;
 		}
 	}
 
 	/* Ensure that ma_mask is octet-aligned */
-	ma_mask := substr(ma_mask, 0, ma_mask_len);
-	ma_mask_len := (ma_mask_len + 8 - 1) / 8;
+	var integer ma_mask_len := (lengthof(ma_mask) + 8 - 1) / 8;
 	ma_mask := f_pad_bit(ma_mask, ma_mask_len * 8, '0'B);
 
 	return { len := ma_mask_len, ma := ma_mask };