Adjusting option cost based on other options
 

In Deus Vult your unit price is based on number of "stands" the unit contains (could be limited to say, 3, 4 and 6). If you buy an upgrade for the unit, such as mail armor, the cost depends on the stand count, 3 stands => 15, 4 stands => 20, 6 stands => 55.

Stands are modeled as options in my datafile. I can set the total cost of the entity correctly in postlink script, but I can't modify cost of Mail option based on the selection of stand count, as option cost is readonly in postlink script.

I could do it in option cost script, but that is really not feasible since the option cost varies for different units...

Any hints how I could solve this?