Makes sense that he would change setups for the type of guitar not for the song tho. and of course have a backup.The 10 bands from what the knowledgable people have said are for stadium eq'ing like feedback problems etc Things that would be ironed out and then taped up at sound check..makes total sense.
I don't even think that is a mxr 6 band eq taped to the amp...looks like a boss 6 band...regardless it's use is unknown...could be for beefing up the signal for the next amp in paralell or what lead guy calls daisy chaining..or it could be an effects loop....just because the amp has 4inputs doesn't mean that one of them could be used as an output for any number of purposes..seems to be a nice place to even add knobs..very common... Here is a pic of the boss 6 band...not the ge-7 but the ge-6, designed to compete against the mxr 6band.
http://www.bossarea.com/loadpage.asp?file=boxes/ge6.xml" onclick="window.open(this.href);return false;
That's funny in the write up it says that boss made there 800hz slider the center because the mxr 's center was 1Khz.....you mean to tell me that the mxr's drifted so much in value that they(boss) even thought they were boosting the 1khz range? 
