vba - convert formulas to values when specific criteria is met

I have a workbook that is used for billing and it looks up overtime rates in another workbook. Essentially, column A is the person's ID number. Column B is the type of pay (regular, holiday, overtime, etc.). Column C is a formula that looks in different places for their rates based on the type of pay.

I am looking for a code that will scroll through each row on each spreadsheet.

If value in "B3" = "overtime", then convert formula to value in "C3"

The concern is that without this macro, if their overtime rate changes then past data that was entered is no longer accurate.

Thanks in advance!

Thank you so much for the quick reply. Screen Shot 2017-12-18 at 9.14.34 PM.png

Attached is a screenshot of the sheet. The code seems like it is converting every cell in the sheet, but I could be wrong. I also added to the top "dim cl as range" but I'm also not sure if that was correct. Maybe that's why it went through every cell? Clearly my original post simplified the columns. It isn't really A, B, and C.