What are all of the cost rollup overhead percentage pre-requisites?

Hello!

We are working on implementing process standard costing for our business in Oracle EBS R12. We have done all the setups and have created overhead percentages in a non-prod environment. When I do a rollup, some items apply the overheads but some items don't. The setups are based on an Item Cost Class that is applied to each item.

Ex: Transfer Price is 150% for all items in the Purchased (US) category.

Some items in that category will apply overheads but some items will not. I have checked to make sure the non-working items are allowed in the org I am rolling, and I have checked all the setups. All seem to be correct, otherwise the other items would not work either.