Yeah, I'm okay with older powers costing more to retcon, but having to pay to undo every choice made since then, only to put it all back after, makes it prohibitively expensive. I get that they probably don't want people changing their build before every mission, but I do want to be able to make changes when I've made a choice I regret. The powerhouse is great for testing your powers, but until you can actually try them out in real combat scenarios you really won't get a solid feel for how they all work together.