CosmoKramers suggestion is on the mark. However, I would put the criteria in the query so I could sort on it.
I would add these two fields to your query:
Regular Hours: IIf([totalhours]<40,[totalhours],40)
Overtime Hours: IIf([totalhours]>40,([totalhours]-40),0)
Now you have the two fields that actually total to the correct number of hours
This works fine for me and I can sort by these new fields (for example, sort the report by most overtime hours in descending order.
Hope that makes sense.
Fred