I have a Winnebago Journey with a single step. I had it changed to a double step. It was not just a simple swap out. I had to have it professionally done. After installation, I had nothing but trouble with it being unstable and even snapping off the bolt. I ended up having it replaced. Even after replacement, I still had issues. I ended up reverting back to the single step and just invested in a good portable step. I have had no issues after going back to the single step. My take is, I wouldn't stray from the original manufacturers recommendation. It was nothing but expensive heartache for me.
Steve