Hello Rudresh,
I am just wondering if the Scheduling is happening correctly in your case. If you are using BAPI, I really doubt if it does scheduling in APO since it only looks for the available quantity for the date that you have passed.
But, I have a question here ? Why don't you use the standard /SAPAPO/AC04 transaction to do the simulation to see if the rule is getting picked up or not ? You don't have to explicitly use a BAPI to test this.
Hope this helps
Babu Kilari
SCM APO Consultant