My 78 100/7 has two crosspieces and as yours is very easy to use.
I've recently bought an 81 that has a stand with a single crosspiece, a checked plate on the left hand foot of the stand for pressing it down with and a folded steel tang for dropping the stand down. I have an 83 R80TIC with a single crosspiece, no chequered plate and a straight steel bar coming out of the side for dropping the stand, very similar to Blues stand in your photograph but without the bend in the side bar.
The 81 also has shorter springs than the later stand.
Be nice to get to the bottom of this. I suspect that many of the 81/early 82 machines are fitted with the wrong stands.