If he has the 15 psi WGA on his 3071R and has an aftermarket IC and exhaust it will not run anywhere near 15 psi it will run between 22 and 28.I don't think you're running a valid test. Follow me here... The WG passage and the "flapper" are the same item for any level of boost wanted on the 3071, so the WG must flow enough air (exhaust) to control boost all the way up to the max the turbo can flow. If you run WG only, the boost output will likely settle at ~15psi for the 15 psi WGA. It may only take 5-10mm of flapper opening to achieve it. If the WG flapper were fully open at your 15 psi input, the 3071 WG could not control boost at 22+ psi. Your boost controller must be adjusted to hit the actual level of boost you want to run. My theory...
Mine with IC, DP and no cats ran 22 psi minimum but with my cutout open it wouldn't go below 28 psi. I even ran the WGA looped back on the outlet from the turbo (= 0 additional boost) and still wouldn't work right. This is why you have to run the 7psi ATP WGA.