ACCOUNTING FOR CONTRACT ASSET

There is different methods given to account for contract assets in bpp & kaplan which method should i follow –

kaplan method –
cost incurred up to date xxx
(add/less) profit/loss xxx
(less) amount billed (xxx)
contract asset =XXX

bpp method –
revenue recognized xxx
(less) amount billed xxx
contract asset =XXX

in most cases both the method would give me same answer but in cases when cost recognized up to date is more than the cost recognized the answer differs?

WHICH METHOD SHOULD I FOLLOW I AM REALLY CONFUSED IN THIS CHAPTER SO I REFFERED BOTH THE BOOKS