Gotcha. Well it will be interesting to see the results. It's nothing you don't know, but the effort required for an AMRAP is so different than what's done for a max single. No big deal if you are not training or testing for a "true" 1RM though when your numbers are going up all over the place anyway. A fatigued 285x1 that's solid will give us an indication of what you could achieve if you were recovered and peaking.
Plus all of this crazy high rep stuff burns a ton of calories, so you can join me in the land of nomzies