Mix and Match and Discounting using HQ is very diffcult if you require more than one location to have different discounts for the same product.
EG:
Item 123 @ Store A is Discount on Mix and match but isnt at Store B
Although the above can be applied there is much difficulty in turning that discount back off or having 2 types of discount for the same product in different regions.
HQ control over discounts with time control and reporting over the items on discounts should be made easier for large store deployments.