Utilizing calendar in report script?

Is it possible to take into account LN's calendar days when calculating dates in report script?

I want a particular message to appear if a sales order line is scheduled out beyond 90 days, but I want it to be 90 scheduling days by our 5 day calendar and not 90 full days. Does report script have any functionality built in for this or do I have to just manually query the calendar table?

Thanks for any direction!