[DavidG]

The tech cost shown do include all the pre-requisites. There is actually a fairly easy way to program this. Get all the req techs (and levels) for a component and put them in a list. Then scroll through the list and check if each tech has any required techs. If so add them to the end of the list (if not already in it). By the time you get to the end of the list you have all the requirements.