diff --git a/src/osmo-bts-litecell15/lc15_l1_if.c b/src/osmo-bts-litecell15/lc15_l1_if.c
index 37b7f78..8290a93 100644
--- a/src/osmo-bts-litecell15/lc15_l1_if.c
+++ b/src/osmo-bts-litecell15/lc15_l1_if.c
@@ -203,7 +203,7 @@
 
 	get_meas(&meas, &data_ind->measParam);
 	bts_update_tbf_ta("PH-DATA", data_ind->u32Fn, fl1h->trx_no,
-			  data_ind->u8Tn, qta2ta(meas.bto));
+			  data_ind->u8Tn, sign_qta2ta(meas.bto), false);
 
 	switch (data_ind->sapi) {
 	case GsmL1_Sapi_Pdtch:
@@ -248,7 +248,7 @@
 
 	DEBUGP(DL1IF, "Rx PH-RA.ind");
 	bts_update_tbf_ta("PH-RA", ra_ind->u32Fn, fl1h->trx_no, ra_ind->u8Tn,
-			  qta2ta(ra_ind->measParam.i16BurstTiming));
+			qta2ta(ra_ind->measParam.i16BurstTiming), true);
 
 	return 0;
 }