one feat + 7040 XPs + having the right spell known* + 6 months of campaign time to craft the items +88k gp = 176k gp of limited selection items.
Your formula is correct for explaining the cost of item creation in an ongoing campaign, but I think we're talking about starting high level characters here. In that case "6 months" and even "7040 XP" don't really mean anything. So taking one feat can allow you to have up to double the items of any other party member. Nutty nutty.