my guess is (since he has two) is that he thought he could mount one on each side thus making both sides of the harness adjustable for things like switching between extremes in exposure protection. Tobin specifically says to not do this with this product. It relies on the one side being "anchored" to allow you to snug it to you. If two are used, it likely allows the webbing to be dynamic and the plate would likely be unstable.
The GHA is specifically for allowing you to open up one side of the harness to ease getting in/out.....Don't make ASSUMPTIONS (GUESS) RH-----........Very bad habit in diving.......Was trying/experimenting w/the Glides for something other than what they were designed for, as I do w/a lot of gear............I wonder if you ASSUME (GUESS) your gear is always in working order ??!!........" I guess my Nitrox is what they said"...."I guess my reg's are working" ......"I guess my lights will work".......Do you 'GUESS' everything will be OK when you dive ??!!.....Over 3000 posts, but only 200 dives !!!!.......I G-U-E-S-S you most know what you're GUESSING about !!!!!......Any one want to get in on a 'Pool' to GUESS when RH--------'s name hits the 'obit' column.......He went diving and GUESSED wrong !!!!!!
Its quite effective at that. Maybe he will sell you one of his as it's not for him. A word of caution if buying used: there are two models. The improved second generation only has one webbing slot (DSS cut the second slot off, making it function more the way it was intended).
Like to hear the reason j2s didn't find it to his liking...