I'm calculating the following:

Start time in hh:mm (F3)
End time in hh:mm (F4)
Total time (F5) this cell is been custom formatted with [m] to convert
to minutes and then calculate penalties.

If F5 is under 175 (minutes) I need to find the difference and
multiply x 2
If over 175 I need to find the difference
If 175 there are no penalties.

I'm using the following formula
=IF(H3=0,0,IF(H3<175,((175-H3)*2),IF(H3175,(H3-175),IF(H3=175,0))))

Why do I get 349.6458333 for a value of 255 in F5

Thanks