diff --git a/pcu/PCU_Tests_RAW.ttcn b/pcu/PCU_Tests_RAW.ttcn
index af1ef99d5..6a5f5d005 100644
--- a/pcu/PCU_Tests_RAW.ttcn
+++ b/pcu/PCU_Tests_RAW.ttcn
@@ -912,8 +912,11 @@ testcase TC_ta_ptcch_ul_multi_tbf() runs on RAW_PCU_Test_CT {
 		tai6_ta := ?));
 }
 
-/* Default link quality adaptation (Coding Scheme) ranges:
-/* CS1: ... 6 dB, CS2: 5 .. 8 dB, CS3: 7 .. 13 db, CS4: 12 ... dB */
+/* Default link quality adaptation (Coding Scheme) ranges (inclusive).
+ * OsmoPCU (VTY): cs link-quality-ranges cs1 6 cs2 5 8 cs3 7 13 cs4 12
+ *
+ * NOTE: the ranges are intentionally overlapping because OsmoPCU
+ * does not change CS/MCS on the range borders (5-6, 7-8, 12-13). */
 private template integer CS1_lqual_dB_range := (-infinity .. 6);
 private template integer CS2_lqual_dB_range := (5 .. 8);
 private template integer CS3_lqual_dB_range := (7 .. 13);
@@ -952,14 +955,22 @@ testcase TC_cs_lqual_ul_tbf() runs on RAW_PCU_Test_CT {
 	/* HACK: patch missing TLLI; otherwise OsmoPCU rejects DATA.req */
 	ul_data.data.tlli := '00000001'O;
 
-	/* 16 UL blocks (0 .. 32 dB, step = 2 dB) */
+	/* The actual / old link quality values. We need to keep track of the old
+	 * (basically previous) link quality value, because OsmoPCU actually
+	 * changes the coding scheme if not only the actual, but also the old
+	 * value leaves the current link quality range (window). */
+	var integer lqual := 0;
+	var integer lqual_old;
+
+	/* 16 UL blocks (0 .. 15 dB, step = 1 dB) */
 	for (var integer i := 0; i < 16; i := i + 1) {
 		/* Prepare a new UL block (CV, random payload) */
 		ul_data.data.mac_hdr.countdown := (15 - i);
 		ul_data.data.blocks := { valueof(t_RLCMAC_LLCBLOCK(f_rnd_octstring(10))) };
 
-		/* Link quality in dB and our CS1-4 expectations */
-		var integer lqual := i * 2;
+		/* Update the old / actual link quality */
+		lqual_old := lqual;
+		lqual := i;
 
 		/* Enqueue DATA.ind (both TDMA frame and block numbers to be patched) */
 		log("Sending DATA.ind with link quality (dB): ", lqual);
@@ -971,9 +982,11 @@ testcase TC_cs_lqual_ul_tbf() runs on RAW_PCU_Test_CT {
 		log("Rx Packet Uplink ACK / NACK with Channel Coding Command: ",
 		    dl_block.ctrl.payload.u.ul_ack_nack.gprs.ch_coding_cmd);
 
-		/* Match the received Channel Coding Command */
+		/* Match the received Channel Coding Command. Since we are increasing
+		 * the link quality value on each iteration and not decreasing, there
+		 * is no need to check the both old and current link quality values. */
 		var template ChCodingCommand ch_coding;
-		select (lqual) {
+		select (lqual_old) {
 		case (CS1_lqual_dB_range) { ch_coding := CH_CODING_CS1; }
 		case (CS2_lqual_dB_range) { ch_coding := CH_CODING_CS2; }
 		case (CS3_lqual_dB_range) { ch_coding := CH_CODING_CS3; }