I did not include Other time as a Copilot(MC: Form 4?) in any PIC or SIC.
I did include Other time as a Pilot(MP, IP, EP) in PIC and SIC. As the AC I logged Other time in the aircraft forms but I was still "solely responsible" for the aircraft which should be all PIC. There's a little more to calculating PIC and SIC but that seems to be the way that most ppl I've talked to have included Other time into PIC and SIC.