Today, just after I align GR well (GR transmission is at the level of ~2550counts, with 12.28mW GR injected to FC) to FC, I checked BAB in FC transmission and reflection.
For transmission, the level is 340counts. Then I measured the injected power into FC, it was 0.333mW. By comparing the standard number we recored in WIKI, transmission is misaligned by ~20%. ((340-100)/(392-100)=82%)
For reflection, roughly also 20% is misaligned. (check the last attached picture for reflection in to AMC)
Last time we aligned BAB to FC is this Monday.
I tried to align FC again and the second time, TRA got misalign 60% while reflection is also roughly 20%. So reflection seems to be less sensitive to alignment.