The issue is bigger than this and has been commented in many posts.
It affects in ordering also in case you order by stock or sales only the parent product is counted.
Also affects featured products where childs again are ignored and can't be shown.
Quote from: mark R on April 20, 2016, 13:13:13 PM
example
Parent - Bag
child 1 - Bag Blue - qty sold 5
child 2 - Bag Blue - qty sold 3
Parent Bag = qty 8, should display on module. (for this example this is my best seller, and should be first)
Yes for you and me that is the logic however others use parents and childs in a different way.
I agree this is an issue, childs are ignored by the system in terms of statistics and use of modules.
We have the same situation as you but instead of using that module we tried to order products per sales, since VM doesn't sum up the child sales this reflect a wrong ordering.
I never found out a solution