They press 300 numbered copies and about 25 promo/preview copies. The reason, I am led to believe (and I am not an expert), is that this is the maximum they can press from the Father ... as they do not make Mothers and subsequent stampers (what most records do). The Father is direct from the lacquer (which is destroyed when removing the Father) - so when all these are pressed they cannot re-press them again without cutting a completely new lacquer. That's what I am think is happening here.
The closer to the Father, the better (in general). Look at prices for, say, A1/B1 matrix (stampers) for The Dark Side Of The Moon's -- these fetch a pretty premium over later stampers (i.e., it is further away from the Mother, and, therefore, Father). Sure, the solid blue triangle label helps make these collectible, but the sound from early and late stampers is very very obvious (and I have tinnitus) :-)