Hi - I played around with this briefly. Set up a second range of cells where the top left cell corresponds to the top left cell of the original range(i.e.-B2).
Formula =ROUNDDOWN(B2,0)-B2
copy this formula to all of the cells in the new range. This essentially removes the date from the values. Then in a cell outside of the ranges, use a =(COUNTIF(range:range,">4:29")-COUNTIF(range:range,">5:01))
to count all of the cells with a time value that you indicated wanting to know.
Good luck
