Can anyone tell me what the reduction in air use (basic estimate) when using a DPV (Diver Propulsion Vehicle-Example, Apollo-AV-1)? For scuba/snorkeling?

Will not be riden "saddle" style but with unit in front off/slightly below diver…

Details:
Senario One: Using an expeienced SCUBA diver – 1) No spear-fishing 2) Minimal current 3) Let’s say avg. in water profile (drag), standard fins, 100 cuft tank, properly weighted 3) “Normal” surface air consumption rate (aka- their not a “Hoover” so to speak) 4) Essentiallal using legs as rudders for turns minimal use for propulsion. 5) Speed decent, using lift bag for acent for obvious safty reasons…

Senario 1A: What might I expect if you used it for snorkeling in terms of improved dive depth (normal equalization ability) range and improved submerged time (apnea) since you won’t be using your large muscle groups? NO limits on use for decents/asents…

Thanks – Vance P.

Impossible to answer, even with a "basic estimate". You don’t give a depth for starters, nor how long you’d normally go on that 100cf.
Just take your normal surface consumption (at rest) and then take into consideration the depth you’ll be using the DPV at.
You’re making this far too complicated when it really only boils down to that.
For your free dive, it’s going to depend on how fit you are to figure out, time wise which also translates to how deep or far, you’ll be going. It varies so much from diver to diver that no one is going to be able to give you a number.
Again, you’re making it out to be far more complicated than it is.
In both cases, it’s the diver that is going to be the wild card here and the dive profile in your first scenario.
Sorry Vance, but if you’re trying to justify the cost of a DPV for a recreational diver, as a norm, it ain’t happenin’. It may be if you are an avid wreck or cave diver with transit times in mind or a artifact hunter in a legal area, but as a "Joe Blow" diver, nope. Not unless you have a wife that never sees the bank accounts. 🙂