Add extra validation when changing a product record from Standard to another costing type

In Sage 200 it let's you change the product group on a product record from Standard costing to another cost type even though there are outstanding standard variance posting to be made. Because of this you cannot delete the product records as there is outstanding standard variance postings even though the product record is no longer a standard cost type.

It would be better if the software didn't even let you take it that far. At the point of trying to change the product group extra validation should be added to stop if there are outstanding standard cost variances to post.