IANAE(conomist), but isn't this flawed logic? If he only had to do $70 worth of work to get my $100, then I only had to do $100 worth of work to get the $142, so we're still talking about 30%. Otherwise, doesn't it become a vicious cycle if you just keep chaining services and tax rates together?
(it's been a long day, so my logic could also very well be flawed. Something just seems off about your calculations)