It's supposed to be the Captains signature for P1/S rather than his name.
I still can't quite get my head round this P1/S for PF sectors. I would log P1/S when doing a command conversion course, because you would be in the left hand seat acting as PIC under supervision.
But in the right hand seat, as PF, you might be handling and making some decisions, but your not PIC.
I don't get it.