You should also keep in mind that IB does not change the exchange field of an existing option order when it gets re-routed. For example, you initially put your option sell order at 1.95 through SMART and it gets routed to PHLX, then you change the price to 1.80, and it happens to be re-routed to ISE, but the TWS will still show PHLX (it's kind of a bug, isn't it?). If you now decide to cancel it, you will get a fast confirmation, since your order is really on ISE and not on PHLX anymore.