Freedom of choice is great!
I agree.
The point I was trying to make is that multilevel dives can most certainly be planned using the tables in the event that one's computer decides to crap out, as anything electronic is prone to do from time to time.
True, a multilevel dive calculated using tables will be more conservative, but you won't be losing much time, especially on a single tank dive. Further, by using the information from a day's previous dives to find one's current pressure group, one can easily switch from a computer to the tables, to determine NDLs, for further dives using the tables should one's computer fail.
I have a computer and use it for its convenience. But I also use the tables. I track each dive using the tables so that I know my pressure group (on the tables) at the end of each dive. Should my computer fail, I'm ready for the switch to "old school" in a heartbeat. Having planned my dive using the tables, if my computer should fail during the dive, I can switch to my depth gauge and watch and continue the dive.
For me, the switch from computer to tables is easy and can be done with very little thought or effort. I do realize, however, that the tables are not being taught the way they were when I learned to dive back in 1965 (I was trained by an ex-Navy diver) and that most divers today are taught to rely more heavily on technology to make things easier. So, for them, giving up on the remainder of a day's diving because of computer failure makes sense. For me, a computer is merely a convenience, not a necessity. I can live with it or without it. True, I might lose a few minutes of bottom time on a multilevel dive plan using tables vs. a computer, but that's no big deal. I have plenty of tanks and plenty of time.
An example of a multilevel dive using PADI tables:
90 feet, 10 minutes.
70 feet, 10 minutes.
40 feet, 20 minutes.
Total bottom time: 40 minutes.
Final Pressure Group: P.
This is well within total NDL and leaves more time at 40 ft. if desired and air supply allows.
Since I frequently resort to my "old school" habits, if you ever come to the East Coast of the US to dive, one of those guys you may run into diving a double hose regulator, no BC, no SPG and no computer just might be me. Don't forget to wave!
Paladin