They also say this, but let's cherry pick and put things out of context as we are as transparent as possible and you know it. Clients can check their rebates against the exchange base fee rebate. But as we all know there are outliers and which need to be included in the legal blurb.
IBKR-PRO Tiered Commission Structure for Orders Routed to Exchanges: Under IBKR's Tiered
commission model, IBKR passes to Tiered commission clients some or all of certain rebate payments IBKR receives for executing stock orders at exchanges, although the Tiered commission model is not intended to be a direct pass-through of exchange and third-party fees and rebates. For example, IBKR may receive enhanced rebate payments for exceeding volume thresholds on particular markets, but typically will not directly pass these enhancements to clients. Likewise, IBKR does not pass to clients all of the rebates IBKR may receive for orders in pink sheet or OTCBB stocks.