Quote from jimrockford:
The last time I heard this, I tested the feature, and I immediately discovered that it still did not work, because of multiple bugs, and I submitted one or more trouble tickets or emails, which are no longer available in the system, and if I remember correctly, I was told that the info had been passed on to the developers, and that no info was available as to when the bugs would be fixed. This was a long time ago. Is it possible that the bugs were fixed without any announcement in the release notes?
If I recall, one of the bugs I found, with this feature, was that orders were SMART-routed to NYSE even though auto-ex was barred by the five-cent-rule. I had previously reported this bug, I was told it was fixed, but when I tested it, the same bug happened. I believe the other bug I found was that orders would route to NYSE even though auto-ex was barred by another rule which blocks auto-ex whenever a better price is available on a competing market center, even if that better price is only for 100 shares, or is otherwise not covered by the trade-thru rule.