diff --git a/src/nacc_fsm.c b/src/nacc_fsm.c
index df38927..ba7bbb7 100644
--- a/src/nacc_fsm.c
+++ b/src/nacc_fsm.c
@@ -895,3 +895,10 @@
 		return false;
 	return !osmo_cgi_ps_cmp(&ctx->cgi_ps, cgi_ps);
 }
+
+bool nacc_fsm_exp_ctrl_ack(const struct nacc_fsm_ctx *ctx, uint32_t fn, uint8_t ts)
+{
+	return ctx->fi->state == NACC_ST_WAIT_CELL_CHG_CONTINUE_ACK &&
+	       ctx->continue_poll_fn == fn &&
+	       ctx->continue_poll_ts == ts;
+}
diff --git a/src/nacc_fsm.h b/src/nacc_fsm.h
index 68ebd52..beea0f7 100644
--- a/src/nacc_fsm.h
+++ b/src/nacc_fsm.h
@@ -75,3 +75,5 @@
 
 bool nacc_fsm_is_waiting_si_resolution(const struct nacc_fsm_ctx *ctx,
 				       const struct osmo_cell_global_id_ps *cgi_ps);
+
+bool nacc_fsm_exp_ctrl_ack(const struct nacc_fsm_ctx *ctx, uint32_t fn, uint8_t ts);
diff --git a/src/pdch.cpp b/src/pdch.cpp
index 19d57a2..76acbca 100644
--- a/src/pdch.cpp
+++ b/src/pdch.cpp
@@ -401,8 +401,7 @@
 
 		return;
 	}
-	if (ms->nacc && ms->nacc->fi->state == NACC_ST_WAIT_CELL_CHG_CONTINUE_ACK &&
-	    ms->nacc->continue_poll_fn == fn && ms->nacc->continue_poll_ts == ts_no) {
+	if (ms->nacc && nacc_fsm_exp_ctrl_ack(ms->nacc, fn, ts_no)) {
 		osmo_fsm_inst_dispatch(ms->nacc->fi, NACC_EV_RX_CELL_CHG_CONTINUE_ACK, NULL);
 		/* Don't assume MS is no longer reachable (hence don't free) after this: TS 44.060
 		 * "When the mobile station receives the PACKET CELL CHANGE ORDER
diff --git a/src/tbf.cpp b/src/tbf.cpp
index 61ab90e..0ea013b 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -570,8 +570,8 @@
 		}
 		/* Signal timeout to FSM to reschedule DL assignment */
 		osmo_fsm_inst_dispatch(this->dl_ass_fsm.fi, TBF_DL_ASS_EV_ASS_POLL_TIMEOUT, NULL);
-	} else if (reason == PDCH_ULC_POLL_CELL_CHG_CONTINUE && m_ms->nacc && m_ms->nacc->fi->state == NACC_ST_WAIT_CELL_CHG_CONTINUE_ACK &&
-		   m_ms->nacc->continue_poll_fn == poll_fn && m_ms->nacc->continue_poll_ts == pdch->ts_no) {
+	} else if (reason == PDCH_ULC_POLL_CELL_CHG_CONTINUE &&
+		   m_ms->nacc && nacc_fsm_exp_ctrl_ack(m_ms->nacc, poll_fn, pdch->ts_no)) {
 		/* Timeout waiting for CTRL ACK acking Pkt Cell Change Continue */
 		osmo_fsm_inst_dispatch(m_ms->nacc->fi, NACC_EV_TIMEOUT_CELL_CHG_CONTINUE, NULL);
 		return;