The system automatically performs offsets for requirements dates for components in the MPS/MRP calculations. It also performs offsets for calculation of material need dates at the time that shop orders are released.
To calculate the offset, the system takes the parent lead time from the Item Master and adjusts it by the bill of materials offset (plus or minus) for the component. This gives the lead time days for that specific component. The system starts with the due date of the parent and backs up and skips all non-workdays in the shop calendar.
Note that the offset calculation uses only calendar records that have a blank work center (the calendar record applies to all work centers). See the information for the Shop Calendar Maintenance program, SFC140, in your Shop Floor Control documentation for shop calendar details.