IAS 2 inventory overhead

Dear Tutor, Hope you are fine. Could you please explain how we should calculate the OH in IAS 2? in example 2 of chapter 10 of FR notes you use the budgeted volume. But what about the overhead expense? We should use the BUDGETED overhead or ACTUAL overhead? In that example you calculate 72.000 / 12.000 . What is 72.000. It is the budgeted OH or ACTUAL OH? Thanks