In my test, the planning calendar (MARC-MRPPP) in combination with lot size PK works in MRP calculation date, but not in ATP.
Example: today is 11/17/11 (Thur), my calendar is configured to have deliveries on weekly Tues, Planned delivery time is 6, GR time is 1. MRP will calculate the following date:
11/17 + 6 = 11/23 (Wed). It would then increase the date to the next Tues (11/29)
11/29 + 1 = 11/30 - this is the result for the requisition date.
If I enter a sales order (ATP check to use RLT) and there is not available inventory, I get confirmed date 11/24! The system takes today 11/17 + 6 + 1 = 11/24. But this is 6 days before MRP can confirm it!
How can I activate ATP to check the planning calendar?
If you set ATP to use RLT then during ATP if stock is not Avail then system goes to MRP 3 view & check the field Tot. repl. lead time. You need to set the no. of days here for RLT. As per my knowledge Planning calendar of MRP2 will not be consider.