I looked for signal on MC2 TRANS during the IMC locking at 250mW and found that the QPD does have light and is seeing the locl-unlocked transitions and DC changes (100mW to 250mW).  A plot showing the signals is attached.  

Offsets were hugely wrong for the segments, so SUM is -70 unlocked and -60 locked.  This prompted me to fix the offsets for MC2 TRANS and IM4 TRANS.  New values listed below.

MC2 TRANS

old offsets
15.0
47.0
-6.0
20.0

new offsets
1.4
1.4
1.6
1.8


IM4 TRANS

old offsets
-9.0
-26.0
-26.0
11

new offsets
1.5
0.5
0.7
1.6