TDA is PFO on options big time and that's how it gets low fees. As far as I know, IB actually sends your option trades to exchanges unless disclosed otherwise. It used to own an option exchange Timber Hill before it closed it down citing conflict of interest (real reason I suspect is because it wasn't making money)
Found their page for CBOE fees. But according to that I should pay nothing? (ETF Penny Pilot < 100 contract) But there is also the footnote condition which I don't really know.
This is what you need to look at: https://www.interactivebrokers.com/en/index.php?f=1590&p=options7 You have to add all of the fees together and that's your options commissions PER contract.
Timber Hill never said the reason for shutting was conflict of interest and it was a derivatives market maker and not an option exchange. A side benefit of shutting down was removal of that question by people who never believed TH didn't see IB flow. Yes, TH became less profitable in the US primarily for not getting into the payment for flow and HFT game. With the resources and capital available, it could have easily done so. IB does add/remove exchange liquidity games but do look at quality of execution on those offering flat fees. You can find where they are selling their flow if you search for the firms 606 reports which are publicly available.
I find TOS execution better and my all in costs are a fraction of IB. I spend 28 percent of my profit in commission at TOS .. I provide liquidity and make 2 to 5 cents per trade If I was at IB, there would be no profit.
I have a similar observation, too. The additional commission at IB didn't seem to get me better executions than TOS.