I use a Brut on my stage / O2 bottle. It works fine. I have the DIN adaptor on the reg. When I first picked this reg up I too was worried that it would bleed the pressure on the first stage down after I pressurized it. As it turns out, the dry bleed is so slow that I have not had a problem. Even after a 50min. or so dive I only lose maybe a few hundred PSI.
EDIT: I realize now that the OP and Dive1Dennis were not concerned about overall loss of volume, but that they were considering whether the loss would be enough to un-charge the regulator after it was shut off. Sorry about that....and I was having so much fun with the arithmetic, DARN!
End EDIT
Even at a 30cc/min bleed rate, only 0.07 cubic feet of gas is bled off each hour.
30 cc (cubic centimeters) per minute bleed rate (typical bleed rate is 15-30cc per minute)
30 X 60 = 1800 cc per hour bleed rate
1 inch is 2.5cm (centimeters)
1 foot is 12 X 2.5 = 30 cm
1 cubic foot is 30 X 30 X 30 = 27,000 cc (cubic centimeters)
1800cc (bleed rate per hour) / 27,000cc (cubic centimeters in 1 cubic foot) = 0.067 cubic feet or roughly 0.07 cubic feet per hour bleed rate
On a 3000 psi 40 cf bottle, a loss of 0.07 cubic feet of gas will lower the psi by only a tiny amount:
0.07 / 40 X 3000 = 5.25 psi drop for that tank in one hour from the bleeding off of air
I'd suggest your psi drop of a few hundred psi in less than an hour is due to some other factor, such as a drop in temperature perhaps.
Someone please feel free to check my arithmetic in case I've made a total buffoon of myself!
EDIT: One thing I forgot to add was that the increase in ambient pressure at depth would probably increase the output of the "flow control element" to some extent, although, with the sintered metal element, it probably wouldn't be proportional. End EDIT.
Dave C