To do anything helpfull with the eRDPml that improves upon the tables, you must keep fairly strict track of all you minutes at various levels during the dive (slate, I guess).
I don't see how keeping track minute-by-minute would help. The eRDP
ML acts as either flat tables or the wheel. When used as the wheel, it still requires that your second level be a minimum number of feet shallower than the last depth, for a maximum of four depths.
< edit: - Perhaps I misunderstand your statement. Keeping track of various depths is an additional task that is necessary whether using the Wheel, or the eRDP
ML in the multi-level mode. >
When used as a flat table, there is one minor improvement. The depths are now rounded up in five foot increments instead of ten, presumably to make it similar to the wheel and to simplify design. That caused a few Knowledge Review and Quiz/Exam answers to be changed slightly.
The main advantages of eRDPs are less likelihood of mistakenly changing rows or columns as you move your finger along the narrow sets of numbers, and not having to do the math of adding RNT to ABT. Big whoop! And some people just find them easier to learn.
It's also curious that PADI now sells you this device instead of The Wheel but the Diving Knowledge Workbook contains "Wheel" problems and no reference to the new thing.
The Diving Knowledge Workbook also contains table problems. To differentiate with the eRDP
ML, you simply answer "yes" or "no" when you are asked whether it is a multilevel dive.