Is this coupon possible? Get fixed amount off for each 5 items from a specific category

Question

I want my customer to have a coupon code where they get $4 off for every 5 items they buy from a certain category. For example:

0-4 items from cat A = no discount

5-9 items from cat A = -$4

10-14 items from cat A = -$8

15-19 items from cat A = -$12

etc..

I've been trying all different condition and action rules for over an hour now and can't get this logic right, which I thought should be pretty straight forward.

Answer 1

I've used this extension and it has a ton of additional coupon code configurations: http://amasty.com/special-promotions-pro.html

One of them is a fixed discount for product set. You then set the categories it applies to and the discount step (in this case 4). Place the discount amount as 4 and this should complete your coupon.

Kaylie

Answer 2

You can do this logic, but you should create one rule for every group of quantity. Suppose:
One rule for 5-9 items from cat A = -$4
Another rule for 10-14 items from cat A = -$8
...
Another rule for 50-54 items from cat A = -$20
...etc

But every rule have same structure changing only numbers. See screenshot:

And you should create same rule for another range of quantity.