Er, my bad. Yeah, it's 85 minimum for any subset of the Access Melbourne list other than the two which get you in with a 79. No where is this made clear on the Melb course search pages, though.
From what I was told about AM coming from an under-represented school myself, they basically have a set quota of kids they want to accept under the grounds of Access Melbourne. Say they set aside 20% of the Science course @ Melb for AM kids, they'll arrange you in a list of your ATARs below the 92 clearly in and go down the list. If the last seat is taken by a kid who got 85.55 and your score was 85.50 ... well, too bad. There's sure to be much more criteria weighed than just ATAR (for example, if you got 86 despite scoring a 48 in Biology that was brought down by your 25 Legal Studies score, they'll probably want you in their Science course). It's by no means a gurantee, it's a consideration. I had a good friend from last year who wanted to go to Melbourne too but she scored lower than the minimum and had to settle with Monash despite applying for AM.
Most of my friends slacked off and only put in enough effort to get above the 85, but I kind of went overboard and scored a 93. Too much effort for a score that meant nothing, honestly, but I guess it's too late for me to recommend you try your hardest regardless of Access Melbourne. :V