Its possible that 3rd gear is only used for downshifting into, similar to the Chrysler 6 speeds have 2 4th gears.
I believe I either started a thread here regarding the scan gauge and x-codes or I replied to an existing thread. There was no interest so I don't think I posted them.
Let me know if you find that thread, if so link it here and I'll reply on it and add the codes so it's in a place where others can find it.
One thing about this forum is the search engine is terrible.
I'm generally pleased with the 9A in my '18 Cruze Diesel. It is barely noticeable in most of my driving and is a big improvement over the 6A I had in my '13 Sonic. The only times it "misbehaves" is when I am going downhill and coasting, it stays in a high rev range, or if I am coasting to a turn, and then try to accelerate after turning. But I just deal with it, because once the accelerator pedal is pushed for a bit, the transmission finds its rightful place. As far as stop/start, I have not minded it at all. It is a little annoying in a parking lot, but the start is so seamless, it isn't really that much of an annoyance. Also, I like to keep my cabin as cold as a meat locker, so that might prevent the start/stop from activating as much.