Hi Greeshma,
Unfortunately for CK55 we do not have any FM. But for CK53N we have a long list. Use package as 'CK' in transaction SE37 and check them out whether any of it suits you.
I did not get your this part of question - Can you please suggest how to store 'CKKA_COSTING_PROCESS' from temporary buffer to tables.SO that costing data correctly displayed in VA03.
-> But if you understand how to execute this FM the you can call both FMs in order and it should work. Try this too in SE37.
Coming to the execution mode of ''CKKA_COSTING_PROCESS'FM logically speaking there should not be any difference because this FM has no way of knowing (coz there are no importing parameters) the mode in which it was executed.
PS: - My answers may sound a bit generic here because i haven't worked on PP module.
BR.