FINALLY I'm back out of B- Hell. Played twenty or so games today, first ~15 were just the usual constant back and forth with no real loss or gain anywhere, but for the last five the mode switched to Splat Zones and Walleye Warehouse was one of the maps. Walleye Warehouse Splat Zones is one of the most Aerospray-friendly environments in the game, and sure enough once I got that going I didn't lose a single game until I ranked into B. The other map was Blackbelly Skate Park, which is neutral to bad for Aerospray in Splat Zones, but the game decided to be its uneven self and gave me Warehouse five times in a row, so I didn't have to deal with it. I really should have kept playing and tried to keep the streak going, but I played for too long anyway.
For the record, I saw a lot more B-/B-/B-/B vs/ B-/B-/B/B games today where I won and got +10 or lost and got -10. So I did see that right the first time, very minor differences in rank don't seem to matter. I'm not sure if that was in question, but I wasn't certain I saw it right the first time. I am now. And my final match to rank into B was all B-s vs all Bs, we won, and I didn't even get the benefit of the +12 because I only needed a few points to rank up. Oh well.