That's pretty much how I've muted strings for decades. I didn't realize I was doing it until I watched my hand while playing one time. It just developed on its own and I just do it without thinking. Now I kind of feel better about it. 
As other have said, if it works for you and you're not risking injury, keep it up.
As other have said, if it works for you and you're not risking injury, keep it up.
But in a way, it also makes me glad I learned a relatively proven technique on my own instead of developing something else strange on my own.