bmi(baby) 737's are indeed 'track up', but their Airbus fleet is all 'hdg up'.
When converting from one to the other, nobody even thinks to mention it - you just set the hdg. req'd. & read the trk., or set the trk. and the hdg. is what it is, depending on the wind.
Much easier on the 'bus using the 'flight path vector', then you can fly any trk.you wish, and forget about the drift.,much more useful, v.clever.
Roger Miller.