Positive/Negative Time Formula needed for calculating arrival before/after scheduled shift

I have to determine how much time before or after the scheduled shift someone clocked in.

A	B	C	D
1	Acutal Clock In	Scheduled Clock In	Difference
2	8:36:41 AM	8:30:00 am	########
3	7:55:09 PM	8:00:00 PM	0:04

I have thousands of lines that I need to do this for.....that I will need to re-do every month to thousands of lines of new data

If I do b1-c1 I get a number when the clock in is before the scheduled I get a number (row 2), but I get ###### if the clock in is past the scheduled (row 1), when it should return 0:06.

I'm looking for a formula (if then statement maybe?) that I can copy down almost 2000 rows.

I'm also doing conditional formatting for the row to highlight when the answer is >=0:15; so if I end up with a negative number I will have to figure out how to change the conditional formatting to +- 0:15

Thank you in advance,

CHill

Have you tried simply doing =ABS(Formula)?
=ABS(B1-C1)

I knew it had to be simple. I had tried the =MOD(Formula), but didn't even go to ABS.

Thank you so very much Jdevil - that worked beautifully!