Right after we bought our 311BHS last Spring, I had to have one motor replaced on my Schwintek slide after 4 uses. The dealer never re-synced the motors after they replaced the bad motor so it always was skewed going in or out until I learned how to re-sync the motors. I now also hold the button in for an extra couple of seconds when the slide is done going in or out. I guess that's pretty important to keep things synched. At least that's what I've read several times and so far I haven't had any further issue.