1. From my understanding, many diving agencies don't teach the US Navy Dive Tables anymore.
2. Following the profile set on dive tables is VERY different than real life scenarios and real time algorithm adaptation. These differences can be crucial while at depth and in DECO situations and you know as well as I do that you cannot predict using the US ND tables the actual seabed nor your actual exact depth at all times. This means, IF you've planned your dive to 28m, you need to stay at 28m for the whole dive right? Problem is, you have a DC so you are following the rest of the divers and now your dive computer "fails" mid-dive so you have no idea what calculations apply anymore... OR you've planned your whole dive based on your max depth, you follow it religiously, you are obviously separated from the rest of the group and your bottom time is greatly reduced as a bonus. Nice.
3. You must also be taking notes UW on your slate right? Your dive watch bezel can only be used for one thing at the time... so let's say NO DECO to make a point. Did you noted down your NO DECO stop exactly at the point your DC failed...