I think FP nailed it. It sounds like you are shifting down as you are slowing to a stop. The trans in the SRT is one of the smoothest autos I have ever driven. It really adapts well to your driving style.

The Z4 2.5 I traded in on my SRT had an autostick. I HAD to shift it manually to get any performance at all. On the track it would only hold a gear for a specified time (like around 20 seconds) then shift up. Not a lot of fun when entering a long sweeper or decreasing radius turn (it would shift up in the middle of the turn)

I haven't experienced this with the SRT. It is fun to shift manually, but it being so good at what it does, I have been keeping both hands on the wheel most of the time.

I used to have nothing but sticks but have to admit having an auto and driving on Los Angeles parking lots, um freeways, makes life easier.