Using formula in price determination process for PO

Hi, dear experts,

I would like to define some conditions types for purchasing orders that allow me to calculate an insurance amount using the formula:

Insurance = [CF)((C+F)10%)]T

Where: C is the Gross price, F is the Freight and T is a factor that the user has to input

For that, I define a condition type for gross price, for the freight and for the T value

How can I have to define a condition type to do this operation?

On the other hand, the freight is a percentage of the gross price, but for this operation I need the amount, how can I make reference to this amount? (Result of gross price * freight (%))

Also, there is a link where can I find information regarding the price determination process?

Thanks in advance,

Mairo.