At least, not in my experience. I've reset several to around 35 yards, both cheap and not so cheap, fixed and variable. The fixed was a Bushy 10x42 3200 Tactical, in focus ranged from about 15 yards out to around 100, maybe a little less. I currently have an old, cheap Bushy Sportview 3-9x32 that I've also reparallaxed for 35 yards, at low power it's nice and crisp at 10 yards, at full power it's also good out to 100 or so, not that I shoot air guns at 100 yards. The only problem I've had with this is getting the lock ring loose on one scope, I have a Nikon Prostaff 3-9, really nice optics for the price, but I can't get the lock ring loose to readjust it.
BTW, I think AO scopes are over rated for most air gunners needs, and I also think that 35 yard parallax is about perfect for most, too. Couple fixed parallax with fixed power, and you have a really fast, effective point and shoot sighting system IMO. Later.