Currently, there is no functionality to allow you to review the changes to your standard costs by component (i.e. labor, material, machine time, overhead) before you actually do the cost roll. This functionality would help make the decision on the appropriate cost changes easier. You would be able to see the affect of a cost change and determine if it is appropriate or needs adjusted before committing the change.
To do this now, you need to capture your cost components and export them, make your changes, roll the costs, capture the new cost component amounts and export them, then compare. Then replace the updated costs until you are ready to commit your changes.