I am trying to calculate flight hours using 4 digit 24 hour clock.
For example; an aircraft takes off at 1400 and lands at 1530. It flew for 1
hour and 30 minutes. The flight time should reflect 1.5

I have had limited success using B1-A1/60 but this only works for the first
59 minutes (it also rounds up .5 and I need it to round down).

I know the format to calculate the difference between two times but this
only seems to work if the two times are formatted as a time. This is
unnaceptable in our reports as the time must be four uninterrupted digits
(e.g. 0200 for 2 o'clock, 1050 for 10:50AM, 2345 for 11:45PM etc.)

Any suggestions?