I don't know if my answer is dumb but can't you just press the Tap
Tempo once to DISPLAY the current milliseconds you're at then adjust it
with the Encoder knob by 1ms increments (or more)?
Alright, what I suggested above won't work. Just checked it now. Sorry.
The "show me what the current mS is" when turning the Delay Time knob and being able to adjust it IMMEDIATELY with the Encoder knob for very fine adjustments is a great suggestion though. I second it.
And then also being able to use back and forth the Delay Time knob (for large increments) and the Encoder knob (for small increments) once you are in adjusting mode already.