If I'm the A code, I log the entire flight as PIC. If I'm not the A Code, I count none as PIC, seat time as SIC, and Other as "Other" in its own column. I count Other in my Total Time, but its really useless for anything else.

My method requires actually remembering and recording who was in Command for every mission. That's a lot of extra work that KC-10Fatboy has avoided. His method is fine too: He just simplified the whole thing by applying a conversion factor at the end to account for the average number of times he didn't have the A Code.