In other words, if you get hit at 30% marginal, now you get hit with 33% marginal. Say, the top $5,000 of what you earn is what is going to be affected in this change. That means your take home of that portion of your income was 3500 is now 3,333 - or about $167 less under the "PT thinking it out" plan.
How do you pull back your money to compensate? Drop your income down $5000 gross in order to avoid the loss of $167 on your previous $3500? How do you work out what you would claw back? Does it not hurt you way more than help you? It would seem like additional marginal labour wouldn't be as... motivated, and I agree. I'm just curious about how you see it, from the other side.