I understand the concept of either seat being PIC.
With all due respect you do not understand the concept at all. The F/O sits in the RHS and the PIC sits in the LHS. The pilot not actually flying the aircraft is the pilot handling the radio. Either pilot can fly the aircraft from their respective seats. Their is only one PIC and that person, if not flying the aircraft, will be handling the radios.
In the Norfolk incident the F/O was flying the aircraft from Apia until the go-around from the first approach at which point the PIC took over the flying duties and the F/O then took over the radio duties.
Probably someone else can explain it more clearly but I think Frank you have a "Who's on First" understanding of the situation.