I am having a problem with a formula I've written. Here it is in its original form:

=IF(A8="","",IF((B8-A8)<"4:00","",IF(A8+"4:00"<A$4,"!",A8+"4:00")))
On cells where this should have been returning the last True value ("!"), it was instead coming up blank. After replacing the "" value after IF((B8-A8)<"4:00"... (where the product of B8-A8 was actually 8:30) with "error", I discovered it was because my formula is returning the True value for that condition, even though it is actually false.

I even tried replacing the "4:00" format with the general numeric value of the numbers (i.e. replacing "4:00" with 0.1667.) Running a simple calculation in another cell (B8-A8) confirmed that the result was 8:30 or 0.3542.

So... can anyone tell me why this formula thinks that 8:30 (or 0.3542) is less than 4:00 (0.1667)?

Thanks in advance!