I'm not using the deriving ought from is logical fallacy. I'm simply pointing out the facts, and the logical conclusions from that. But if you want to be all formal with your argumentation, here it is for you in all its simplistic and formal glory:
I think you're just trying to be argumentative/pedantic for no reason that I can think of or immediately see. Besides, you took one interpretation of "should", and I took another; nothing wrong with both. So you can either choose to be pedantic and continue nitpicking, or you can admit you were wrong in accusing me of a logical fallacy, or bask in the glory that you just watched me make an actual fallacy (before my edit).
P1. Taxes are based on percentage of earnings.
P2. More work implies higher pay
P3. You work more
Conclusion1: Your pay is higher
Conclusion2: You will pay higher taxes.