Approval notifications

We would like to use notifications to notify managers when a requisition has not been approved within 4 hours of being submitted.  If we define a holiday calendar and business hours, will the notification process correctly calculate the 4 hours if the requisition is submitted just before close of business on Friday.  For example, if the req is submitted at 4pm, and business hours are 9-5, will the notification be generated at 8pm, or not until 12pm on Monday?

Thanks for any help you can give.