It's not nuanced or difficult, at all.

The legal interpretation provided states that both PIC, and SIC, assigned as crew, taking a turn at the controls, are on the hook for the entire block time of the flight.

That is not a rest issue. That is a flight time limitation issue, but think about it: if your employer records your flight time in a record officially kept by that employer, which you can print out and present to others, including the FAA, which contains an account of your hours, your approaches, and your landings, and that record reflects the block time of the flight, are you really going to attempt to assert otherwise?

The legal interpretation backs up the company.