budget of maintenance order

Hi all

can anyone please tell me about my following doubt----

say a maintenance order has a budget of $2000.when absolute variance of $500 will be exceeded to budget ---whether when the actual costs after completion confirmation exceeds $2500 or when the planned costs of an order exceeds $2500 ?

also whether only planned costs or actual cost or both cost i.e planned & actual costs will be compared with budget & availability check will be done ?please explain in details.

thanks in advance

rgds

rajib