Tried to use PRC1 input offsets in pitch and yaw ro recover recycling gain, instead of SOFT imput offsets. While the carrier recycling gain responds to PRC1 input offsets similarl to soft offsets, the POP_18 couldnt care less. Thus I suspect none of these offsets is able to tackle the core issue.

The next thing to do is to verify that the POP18 signal is actually trustable, and not saturating,  If trustable, it will be the best indication of recycling cavity losses.