Production posting account differences

Dear All,
I am currently confusing about production posting. what are
the different between the 3rd ledger available within
production order / if I read production advanced.ppt training
material, it only focused only to different ledger account,
but do all of them use cost categories ? if not, what else
the cost setup available to fit the production posting type ?
if yes, it means that the different only ledger account
that set in cost categories, work center/work center
group and production group. but what are the mainly purposes
that makes AXAPTA different than other ?
I appreciate your help so much. tks in advance.