Transmission shifting rough, does mercedes have a repair for it? on 2008 Mercedes-Benz R320 CDI

Car has had the transmission software flashed several times. seems to work for a short time. main problem is 3 to 2 and 2 to 1. 2 to 1 is the hardest downshift. Generally the transmission shifting seems erractic, slow and generally very disappointing. i have ehard that mercedes has a repair for the problem but doesn't tell the customer that it is available.

Asked by for the 2008 Mercedes-Benz R320 CDI