I toggled the gain switch on ALIGNMON QPD from HIGH to LOW. Thanks to switching, saturations on SEG 1 and 4 were solved (fig.1). I measured the dark offsets and subtracted them by changing the values in K1:PSL-ALIGNMON_OUTPUT_QPDA1_DC_SEG{1,2,3,4}_OFFSET.

The SDFs related K1:PSL-ALIGNMON_OUTPUT_QPDA1_DC_SEG{1,2,3,4}_OFFSET were accetpted in OBSERVATION.snap (fig.2)