I have a v4.5.x store with multiple root level categories. I'm trying to implement a 10% discount when someone orders quantity of 5 or more, across categories, in a mix-and-match fashion. In other words - as long as the total quantity of all items in the cart is greater than 5, customer gets a 10% discount.

So, the first hurdle is that most of the discount mechanisms don't support percentage discounts (why?). For example, Price Class discounts would probably do the job if I could specify a percentage, but can only specify a dollar amount.

Order Level discounts require that the user be a member of a role, so that doesn't work because we offer anonymous checkout. It's a blanket discount anyway, so since a minimum quantity can't be specified, wouldn''t work anyway.

Of course, Product-level Quantity Discounts aren't an option because they are specific to product.

Am I missing something obvious? I don't see a way to pull this off.