Correct, with the WKM you have three modes, fully manual, ATTI and GPS. ATTI mode is autoleveling with altitude hold, it's both or not at all (manual), when you turn on GPS you get ATTI plus GPS position hold, again all or nothing. With MK autolevel is always on but you can tune it to be as aggressive as you want, anywhere from barely noticeable to it only wants to stay flat and level. It is possible to turn it off in the firmware but I've never done it, I don't find it to be a problem with it tuned to my flying style. I DO like being able to turn the other features on and off as needed rather than being forced to use all or none, lots more flexibility in dealing with changing weather conditions, something we have a lot of near the ocean up here in New England.
I haven't had any problems with settings going back to default but so far I've only done the upgrade on one of my MK, this particular one showing close to 2400 minutes flight time so its memory is well burned in
I'll be doing a second upgrade within the next couple days then I have to order another ACC to do the third since MK.DE limits you to purchasing 2 at a time. I'll probably wait until the board is more readily available and stocked in the US before doing the third, shipping from Germany is a bit too pricey if not ordering a bunch of stuff at once and right now there isn't much that I need to make it worthwhile.
Ken