Option prices not depending on quantity??

[DigitalSpring]

Hello!

 

I'm using OptionType-Feature and Quantity in product_info.

 

My Problem:

The Option Price has to be counted only once - not multiplied with quantity.

 

Example:

Customer selects 50 sqare meters material (->quantity = 50). He selects the option "Add Logo" for 10$

Now the cart calculates 500$ for the Option. But it should be 10$.

 

I thought about dividing the normal option price by the quantity... that would be correct (50*10/50).

 

I tried for hours, but didn't find a solution (Not by myself and neither by Google).

Please help me!!