I had an issue with my Aqualung I770r the other day between dives for some unknown reason it froze up saving the dive profile 10 minutes into the SI. I didn't have a backup computer but did the second dive on gauges loaned to me from the dive operation ( used 45 min bottom time @ 80 ft 35% nitrox table to do it). I didn't go on the afternoon dives I had scheduled that day because of the issue even though the dive op offered to rent me a computer. I just felt that it was better to call the day than to keep diving without the complete mornings profile on the computer I would have rented. That said I want to get a backup computer just incase this happens ever again. What I am wanting opinions on is should I get one with the same algorithms for NDL or not really worry about that part? I don't intend to get an AI model as I have a backup SPG already. I would setup the backup and take on the dives with me but only to use it to continue a day's diving should the primary ever lockup again.
Good call IMO.