How they calculate, i donno la. But for stamping, bring your document, go to the area designated for stamping at lhdn, they provide a few pc, wait for your turn, and there are some officers standby to help ppl key in correct data, + submit. U will know the price there.

I direct walk in only, no problem.

Stamping cost depends on the value of that contract. No need to know much lah, just let them calculate automatically ( as long as info keyed in correctly.)