How to create condition type with complicated condition base value

Hi experts,

I need to create a condition type for below formula.

COFINS-Import = Service Value x COFINS-Import Rate x ((1 + ISS Rate)/(1- PIS-Import Rate – COFINS-Import Rate))

As you can see basically it is calculated by percentage but the basis value is very complicated btw. currently the value for rates is not kept in any place. Please kindly advise how can I realize it?

Thank you.

Sincerely,
Patrick