There's nothing to prevent two people from both reasonably satisfying themselves that those checks have been made, nor is there a requirement to identify the commander in 'booking out'. And of course very often, the actions themselves are delegated. No single action required by law uniquely identifies the commander.
The nonsense is yours,it says commander not commanders.
I think all bookworm was saying (and I agree) is that it is possible for more than one person can be eligible (in terms of the ANO) to be commander and therefore while obviously there is only one at a time there is nothing to prevent a change in the air.