How do I make quantity discounts apply to Sale products?

I have quantity settings currently set to discount type percentage and discount priced from special.
This works for Specials, but not for Sale products.

What is the correct setting for this? Or does it need custom code?

I looked in the products_quantity_discounts.php file and I see it uses the zen_get_products_special_price fuction, which is supposed to get both Sales and Specials so I don't understand why it doesn't work with Sale products.

I tried changing the function
from
zen_get_products_special_price
to
zen_get_products_actual_price
This does make it display the prices correctly, but when the product is added to the cart the discount is still calculated from base price.