I think that Dr. G is using his opposite side leg on the non maximal attempts and then as he works his way up in weight he goes with the same leg all the time.
I know that we had a discussion about this, hopefully he will see this and post.
As of now I always jerk with the same leg forward. I try to remember when warming up to alternate but usually forget.
What we think, or what we know, or what we believe, is in the end, of little consequence. The only thing of consequence is what we do. -John Ruskin