This is really interesting, because lot of people that i know say the same thing.

Also people using a swagelok micrometric valve with a normal first stage are ready to swear that there is no bigger flow with the depth.

Mi plan for the next test is to go at 40 meter with a one liter bottle and a needle valve, open the gas for 10 minutes, note the difference on the spg, close, then do it again at 30m, then 20m and so on to the surface, to convince the friend who tested with me the flow that there is a variation with the depth, because he is still not convinced.



The clever part of the needle valve is that have a double diameter, thinner at the tip, biger at the base, so can be used to adjust a smal flow (for CCR) and a bigger flow (for SCR).

But no magic to maintain a a flow with the IP augmenting.