Delayed scheduling is a new functionality in R12.1. A new profile is introduced for this functionality
Profile option: OM: Delay Scheduling = Yes
If the above profile is set to Yes then the scheduling of a line is performed only when the changes made are committed to the database, as opposed to simply navigating out of the line record.
Note: In fact, this new feature works only when the auto scheduling is done & the below profile is set.
Profile option: OM: AutoSchedule = Yes
This new feature enhances the overall performance of the sales order window, as only one MRP Call will be made during saving rather than individual MRP calls for each line.
So, for example if you have over 100 order lines and if we save after entering them then Scheduling of all the order lines happens at a single instance.