That's just a Powervalve (That's what we called them then, on old AFB's and ThermoQuads) issue then. Very simple, and cheap fix. Might need a slight retune after. Bad news, gotta tear it completely down to do it. Simple rebuild kit should solve it, doesn't sound like he needs any hot rod parts in it. In some cases, since the AFB primary throttle shaft pretty much runs everything, could be bent or worn substantially. On old Carters, I can see this, not on a reasonably new Edelbrock.
LOL! I wouldn't do that with it! I kinda feel that way about my Holleys QUITE often, lol. They ain't that user friendly either. All in what you're used to.
BUT, on your side of things, I think he's leaving some performance on the table in CFM, depending on his engine and build. I think most of us agree that 750-850 CFM on a mild build is where we should be on most Big Block engines. The Eddie MAY be leaving a little to be desired in that respect. But what you just described is normal, just with slight PV issues. There's not a screw on the thing to fix that.
Ray