[zarlor]

Well, the relevant line from that middle post is only what is inside the foreach-nexteach lines, since those lines are trying to walk through the skills to just find the Knowledge ones. So the double cost part is:

 eachpick.field[advCost].value *= 2

That is going through "eachpick", though, so instead you'd need to change eachpick.field with the skill name instead, I think? So maybe something like:

 Skill.skMyCustomSkill[advCost].value *=2

I'm not positive about that, though.