Just managed to reset Assyst on my '15 chassis '16 Winnebago Era 170C. Every source I found did not reset mine.
I have a pair of round 4 button controls on my wheel. The no buttons or the buttons between the spokes versions did not work for me. Since I tend to do my own work, if possible, and since MB really doesn't want me to, I located a huge (30 gig) MB service/parts manual on Ebay. I downloaded it to an old hard drive in a USB box as I wasn't sure how safe it might be. Long story short, It runs as a virtual machine, is a bit slow and a bit difficult to use. No wonder MB needs your VIN to get the correct windshield washer fluid for you.
The attached file is from that manual. The tail end of it was redundant as in my case as it reset before the instructions were telling me to repeat part of the procedure.
I hope this helps someone down the road.
The upside of the download was it covers my RV, T1N and Metris service vans and Lord knows how many other MB vehicles.
Ross