I think it's as you say mate but i have been talking to Lofty via email here too and it's a bit odd to be honest.
It's perfect at EVERY range but 20 yards.
18 yards 22 yards..perfect...
20 yards..a bit hazy ???
It has the premier ret fitted too mate yea.
It's also got the x35 mag booster.
PM me your email and i will send you a few pics etc.