Upgrade to 5.0, costing issues?

I am planning on upgrading from 4.0 to 5.0 this weekend. I remember several
users talking about job costing issues after upgrading to 5.0.

We have several jobs that are open with partial shipments made against them
so far and I was wondering if anyone who has upgraded recently has had any
of those same costing issues.

I really don't want to delay upgrading any longer, but at the same time, my
controller and president will shoot me if after the upgrade our jobs or wip
are not costed properly. (BTW, we have the inventory interface turned off
if that makes a difference).