Specific Price Issue With Quantities And Attributes

[wimogas]

I have 1 product with 4 attributes (silver, gray, black, gold) and each has Specific Prices for Quantities (500, 1000, 2000, 5000) but Prestashop changes unit price as if the Quantities of each Attribute where summed up as 1 product, why?

 

Here's the example:

http://mingproductions.com/mpbc/pencils/54-graphite-pencils.html

 

Try adding to the cart 500 Black and then Go back and Add 1000 Gold and the unit price for Black will have changed:

 

Black:

500 at 0.86

1000 at 0.78

 

It should stay as 0.86, but it changes...

 

What is going on?

 

Thanks!

 

G