determinate price condition type in good receipt

Hi guys

I have defined two price condition types for purchase order, the first one has a fixed value and the other one is variable.

So if I create a purchase order with quantity less than 50 units, the price is calculated using the fixed condition type, otherwise if I create a purchase order with more than 50 units, the price is calculated according to the variable price condition, that is in a example:

Purchase order for X units

if X <= 50 then purchase price = 50 €

if X > 50 then purchase price = X * 0,90€

The problem is in good receipt especially when the quantity differs from the order.

For example: I order 60 units (purchase price 60unidades * 0.9 € = 54 €) but in the moment of good receipt, if I notify just 30 units, te valuation stock is (30 units* 0,9 € = 27 €), in my case I need that the incoming stock will be valuated with the fixed condition type so valuation stock is = 50 €

I would like to know if there is a solution to re determinate the condition type when I post Good receipt

Anyone has any suggestions to fix this?

Thank you very much