Hi max,
I think you don't speak from the same problem.
My taxes are working very well.
But i use default rules for most products(calculated by country EU or NOT EU).
Now, if i need to use another taxe for overide, i cannot set 2 taxes. You have no "parent taxe group" to do this and cannot have 2 taxes(calculated by country EU or NOT EU), but only one.
If you need to apply discount for a group of product for a certain period(not using category, but by product id) you cannot set another discount in same category for eg. and choose priority
I can give you more case, if you need.
Regards,
Patrick