I've tested this contribution, seems to be working quite well.
However, I noticed one problem I'm trying to fix.
I have products in CAT1, and CAT1 offers free shipping for all products in CAT1 - Works great.
However, I can't get Free shipping to work if I add products from CAT1 and CAT2 ( Free shipping is not allowd for the products from this CAT2 ) both at a time in my cart.
Any ideas?
Thanks in advance !!