After getting a partial fill on AMEX (the only exchange which handles SANM options), I lost my place in line, and someone else came before me for the next fill. That did not make sense to me. I contacted IB and complained about AMEX, but this is what IB responded to me: "Dear Trader, Yes I have verified this with both the AMEX and our programmers. Because the order was SMART routed our system re-evaluated the order status and re-routed. Going forward in order to prevent this, you can directly route the order to the exchange it's self." Re-evaluation??? If you're started to get your order filled, why is there any need for further evaluation??