diff --git a/libs/ardour/audio_unit.cc b/libs/ardour/audio_unit.cc
index 15b63c8f37..6a927680aa 100644
--- a/libs/ardour/audio_unit.cc
+++ b/libs/ardour/audio_unit.cc
@@ -1810,8 +1810,8 @@ AUPlugin::get_musical_time_location_callback (UInt32*   outDeltaSampleOffsetToNe
 			*outDeltaSampleOffsetToNextBeat = 0;
 		} else {
 			*outDeltaSampleOffsetToNextBeat = (UInt32)
-				floor (((Timecode::BBT_Time::ticks_per_beat - bbt.ticks)/Timecode::BBT_Time::ticks_per_beat) * // fraction of a beat to next beat
-				       metric.tempo().frames_per_beat (_session.frame_rate())); // frames per beat
+				double beat_frac_to_next = (Timecode::BBT_Time::ticks_per_beat - bbt.ticks) / Timecode::BBT_Time::ticks_per_beat ;
+				tmap.frame_at_beat (tmap.beat_at_frame (_session.transport_frame() + input_offset) + beat_frac_to_next);
 		}
 	}
 
diff --git a/libs/ardour/midi_clock_slave.cc b/libs/ardour/midi_clock_slave.cc
index 8c95272fde..44bb31e05c 100644
--- a/libs/ardour/midi_clock_slave.cc
+++ b/libs/ardour/midi_clock_slave.cc
@@ -83,7 +83,7 @@ void
 MIDIClock_Slave::calculate_one_ppqn_in_frames_at(framepos_t time)
 {
 	const Tempo& current_tempo = session->tempo_map().tempo_at(time);
-	double frames_per_beat = current_tempo.frames_per_beat(session->frame_rate());
+	double frames_per_beat = session->tempo_map().frames_per_beat_at (time, session->frame_rate());
 
 	double quarter_notes_per_beat = 4.0 / current_tempo.note_type();
 	double frames_per_quarter_note = frames_per_beat / quarter_notes_per_beat;