How to obtain the calculation rule inheritance working correctly?

[guidocx842]

Good morning everybody!
Do you know why, if is set a calculation rule to a parent product, all the children products inherit that calculation rule instead using their own calculation rule that I set into each child product? I was sure that parent inheritance works since the children don't re-define a property over the property defined by the parent product...  I'm using stockable variants plugin and all variants (children) need to have different calculation rule (different discount) of the one defined for the parent product. Thanks a lot!!!