Im using Prestashop 1.3.x and also tried it on v1.4.x version We have a store with 2 customers groups: "default" and "loyalty card" The loyalty card membership grants a 10% discount in all store products, but non-cumulative with other reductions. The Problem: Customer groups discounts are always cumulative with other prices-drops, vouchers, reductions, etc. That's a problem on Sales period, cause a loyalty card member can purchase a product on-sale with a reduction of (50% + 10%). Checking "default" as default group doesnt solve de problem, because they doesnt receive any discount in non-on-sale products. Can I develop a way to do not apply de group reduction when a product have a price reduction yet? Prestashop 1.4 has a more complex tool to configure discounts, but theres no feature to add a price reduction by default to whole store products or category products. (except group reductions, that are of course cumulative as i said before) (Note: My store has more than 15000 products) I would be a nice improvement to add 2 checkboxes check box with "Cumulative with other vouchers" "Cumulative with price reductions" in the group config panel, just the same as the voucher tab.