I never remember to put the gear into 1 or 14 before disconnecting the EX box. But, no big deal.
Last time I had the wheel off and then put the EX box back on, my shifter said I had gears 1 thru 12. That meant that when the shifter said I was in 12, I really was in the highest gear (14) so I simply left the hub in the highest gear, disconnected the EX box and reset the twist shifter to the highest gear (14) and reassembled.
Maybe two minutes. If it was more complicated, that would force me to learn my lesson better and always remember to put it into 1 or 14 before removal.