WM-PP interface - costs missing --> staging not done

Tothegether with a PP consultant, I face the following issue:

Given PP orders, for which WM pick parts are to be taken from the warehouse. We only can do this if first the costing is finished.

I don't see:

* Is what we see right : does costing NEED to be finished before we can stage?

* If yes: Why costing already needs to be done? Practically, the production process is long - and not all component costs are know when production starts

* If no - where can we switch this off??

* Or... are we on the wrong track?

Thanks for any help!!!

Jan