I went into BSC2 this afternoon and unlocked and rebalanced the ISI. I started by removing 2 kg of optical table mass in a pattern roughly evenly distributed around the SUS. I then unlocked St2 and looked at CPS's, but the level was still slightly out of spec. I then removed some side wall mass from St2 (a D071200 t1), which brought St2 into spec. I then unlocked St1, took another look at cps's, found everything happy enough, so I packed up. I left the ISI unlocked as I'm hoping to run tf's soon.