You missed out the affect mothballing has upon fleet burn speed limit, sensor & detection ranges.
It's also not obvious (without actually doing it) what happens to a ship's CR if it is just momentarily mothballed.
As it turns out, toggling mothball has no affect so long as 0 time passes, however if just 1 game tick passes, all CR is lost - not very intuitive or consistent behaviour.
CR of mothballed ships should tick down in the same way a ship without supplies does, or even a little slower, given that the ship is only utilizing its engines.