Also, for those that are unclear, Ameritrade does not allow you to put limit orders in the 5 digits, but the MM is free to fill you in the 5 digits.
I've been filled in the 5 digits several times but the actual limit order, of course, was 4 digits.
We have reviewed this repeatedly over the past 8 months. It's nothing new or impossible. I am suprised though that they filled you at .00015 vs. let's say .00019 which would seem more likely.