Works, unless the time difference changes from PM to AM
=(Format([PUSH1PRODUCTION_TIME_TUB_STOP]-[PUSH1PRODUCTION_TIME_TUB_START],"hh")*60)+Format([PUSH1PRODUCTION_TIME_TUB_STOP]-[PUSH1PRODUCTION_TIME_TUB_START],"nn")
1, start = 4:10 AM stop = 5:00 AM Total = 50.00 correct
2, start = 5:05 AM stop = 6:00 AM Total = 55.00 correct
3, start = 11:00 PM stop = 12:15 AM Total = 1365.00 incorrect
#3 Total should be 75.00
EDIT:
Ok this works
=IIf([Start_Time]<[Stop_Time],DateDiff("n",[Start_Time],[Stop_Time]),1440-DateDiff("n",[Stop_Time],[Start_Time]))
1440 = 24hrs * 60min
So if the time difference overlapps 12 midnight then I subtract 1440 minutes (24 hours)
You can change "n" to "h" if you only want to track hours