Setting a quantity discount with items with varying attributes?

Alright, I'm working in 1.3.8 :) I'm still trying to get the hang of this attributes stuff so if I'm overlooking something extraordinarily silly, please forgive me.

I am selling shirts. I would like to offer a bulk discount for a certain type of shirt. However since it comes in multiple sizes, I am having trouble getting it to allow this. It will apply the discount if I buy 10 mediums's, but not if I buy 5 smalls and 5 mediums. How can I get the quantity discount to apply as long as it is the same product regardless of the other attributes?

So far, I am thinking of just adding a text box attribute and to ask the customer to input the total amount into their cart and to specify how many they want of each size in the text box... But if this can be done using the cart, I'd prefer that.

Thanks! :) :clap:

There's a fix you need to apply in 1.3.8:

http://www.zen-cart.com/forum/showpost.php?p=610860&postcount=24

Oh this worked like a charm. I had people ordering 24 of a product that was available in different coloured attributes. And it was giving some at the quantity discount and not others. I was having to refund the difference. Added the 2 lines of code and it works! :)

Thank you!

Sharni
https://www.nappyshoppe.com