Your comments regarding commissions and routing are incorrect. Fair enough if you want to seek more leverage elsewhere but do get your facts straight if posting.
1. If you choose tiered ("cost plus") pricing, you receive exchange rebates.
2. You state "IB rout[e]s my order to exchanges where they make the most out of" but you omit that for the fixed fee of 1/2 penny a share all exchange fees and rebates are included. More importantly, you leave out IBSmart provides better executions and price improvements than the industry (independently audited). First and foremost obtaining the best price possible for clients is the aim of IBSmart routing.
Furthermore, take a look at the myriad of algos available. You even have the option for IBSmart to look for the best rebate.
https://www.interactivebrokers.com.hk/en/index.php?f=4985
and I quote:
For stocks, clients with the Cost Plus pricing structure can elect to have their non-marketable orders routed to:
- The exchange with the highest rebate.
- The listing exchange on the symbol.
- The highest volume exchange that has a rebate for adding liquidity.
- The highest volume exchange that charges the lowest fee for taking liquidity.
https://www.interactivebrokers.com/en/index.php?f=1685&ns=T