First of all, I see this is your first post. Let me be the first to welcome you to IRV2. I thnik you'll find there's some great folks on this forum that are more than willing toi help out.
AS to the spacer - I don't think that's the right way to do it. Springs are designed to have a given compression rate for a given load rating. If a set of new springs allows your coach to sag, then one side is significantly heavier than the other. Sometimes a spacer is put in place to raise that side but unfortunately that is only a band-aid and really not the best way to fix it. In this situation as the coach bounces down the road it won't bounce up and down because the heavily loaded spring is already somewhat compressed. In this case the coach will bob to one side every time it bounces up and down. There should be a heavier spring put in to handle the heavier load or, ideally, ther weight would be better balanced.
Sometimes a sagging spring that has lost it's tension is "fixed" by adding a spacer. This too is not right because the body can bottom out on the stops. Because your coach is leaning to the opposite side as the spacer I tend to think that is what is happening. It's possible that someone put a spacer on that side to compensate for a previous lean caused by a weak spring. Now that the springs have aged and are both weak the spacer is tilting the coach to the opposite side.
That's my guess anyway.