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I don't think the trial version allows deco gases >40 or 50% O2.
Decoplanner is what GUE uses. For what it's worth you can arrive at similar ascent profiles with either program if the gradient factors or conservatism is adjusted. Of course the "ifs" are important. As already mentioned V-planner has some addtional tools for gas planning and mixing which I do not believe Decoplanner does (but then I have not seen Decoplanner in a long time).
CanDive...I am also deliberating which software I should invest into. Not having settled yet on the specific multi-gas, gas switching dive computer I will acquire in the very near future for Adv nitrox/deco procs, I just want to make sure that the software I eventually pick closely emulates the algorithm of the computer if not it becomes a clash of too many simultaneous experiments.