I tweaked CARM offset (K1:LSC-CARM_SERVO_OFS_COM_CALI_OFFSET) from -40 to +40 with a step of 10 to find the good offset.
Figure 1 shows the spectrum with the various CARM offset (offset value can be seen in the legend of the graph).
The best sensitivity curve was also plotted for the reference.
There seems no significant change by tweaking CARM offset, so CARM offset adjustment doesn't seem effective.