Working on maximizer-related things this week...
As Slyz points out, maximizer "hijacks" slots 7,8,11, and 12 for its own purposes so they are perhaps not what you'd expect them to be. You can mostly ignore them and look at the other slots, which make more sense.
In the output of "2 dump", each item's score is basically your current score plus whatever your score would be with that item equipped. There are some other nuances, but that's basically it. The maximizer sorts those scores and then picks some useful number off the end to use in the slot shortlist (where "useful" varies based on a number of things). Then with the various shortlists, combinatorics happens and you end up at your final result.
r12077 documents "dump" in the help text.