No forumla change has been made to the Optimum wash that I know of. The only formula changes that I know of were to OCW (version 2) and the new ONR.
From what I remember the new formula was came out like 2 years ago or something and the only change was they made it more concentrated.
OCW was tweaked a while back to give it more gloss and slickness. I have both versions and V2 is much better.
The reason I am asking is when I ordered it it showed a pic with the new formula sticker but when I got mine it did not have one. don't know if there is a difference.
They may of stopped putting the sticker on if enough time has passed from formula change that there would be no confusion anymore.