when I send an order using IB smart API, IB sends my order to, say, ISLD. but then the order is executed instead at ARCA. the commission for 100 shares if executed at original ISLD is 0.2, now it is 1 dollar for 100 shares since IB re-route the order to ARCA. can I disable IB re-routing?
I don’t think so. I was trying to do post-only configuration but I don’t think it works. Maybe there’s a way to specify one of their algos which joins the bid/ask. Hard to get a reliable answer as you know.
You don't have control over which exchange order gets executed at with SMART. Depending on a volume/type of your trading FIXED commissions might help, at least making them predictable.