Yea that's the problem with tuning these things, same with tarrifs, just leads to companies having a rational reason to spend money on lobbyists. IMO the VAT would be much simpler as a flat tax than trying to tune it, but it's not as popular with people who then complain when the price of goods go up (despite the fact that you'd have to be spending something like $120k a year in order to offset the losses of a 10% VAT with 100% pass-through (in Europe it's only 50%) with a $12k/year UBI)