Case :

I'm selling printed products. In this case, wooden rulers.  I want to add a variant to print on the 2nd side of the wooden ruler.  So I've created a variant to add an extra price.

I've also created a price list for my product with a fixed price per minimum quantity. 

On the web shop, the variant price increases for each quantity of the product, until I reach a price from the additional price list.  When I reach 20 pieces for example, the extra variant cost per quantity is not added anymore.

How to solve this?