In my moms old 97 C280 (now gone), we had nothing but tranny problems. When approaching a stop sign, you could feel the tranny banging gears....4...3....2....1 VERY annoying. Dealership replaced the computer I think twice. No difference. This was the first year of that tranny and I personally think it has alot of glitches that cant be fixed cheaply. I liked the mechanical 4 speed one alot better.
That was part of the reason we got rid of that car. Once the warranty ran out, service bills would be outrageous. It spent most of its 3 and a half years in the shop anyways.
So to answer your question, I would say what your experiencing is normal for this tranny, unfortunetely. But I know the hassle with what your going through. Dealers are of no help, just give you lip service. Least thats what they did with us.
93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K