They exaggerate their claims, plain and simple. A given battery only hold so many watt hours of energy, so unless one light has a much more efficient emitter then the other (and there isn't anything that is that much more efficient then the Q5 right now) it can't produce more lumes without sacrificing run time.
A good example of this is the TK11. Fenix claims 225 lumens for 2.7 hours with an 18650. Sure the light makes 225 lumens with a fresh battery and sure it goes 2.7 hours before output falls to 50%, but in no way does it make 225 lumens for 2.7 hours. As reviews, and my real life experience, has shown the TK11 falls out of regulation very quickly and output diminishes throughout the run time. Compared to other lights which claim 225 lumen for 1.5 hours on an 18650 and hold flat regulation. That's not to say the TK11 is bad, I'm happy with mine, it just can't break the rules.