I was recently asked to help a colleague figure out some date calculations based on a schedule. The requirement was to calculate a future date based on the existing value of a date/time field. I decided to document this solution (and come up with a solution for a similar problem...date addition from the current date/time based on a schedule). Working with dates and schedules can really be a pain if you don't have good examples to work from so hopefully these help somebody at some point. Read on for the full scripts.

http://www.servicenowguru.com/scripting/business-rules-scripting/schedule-time-addition/