Spell DC is determined by:
10 + Spell Level + Casting Stat Modifier + Items + Feats = DC
So what does the Magister "Master of (school)" do for you? What spells are we using where increasing the caster level and max caster level matter?
As far as I can tell it will not change the DC. Will increasing the caster level increase the spell pen? (It could since spell pen uses caster level, does it?) Is that what is intended here?
Increasing the duration of the spell when you are already level 25ish, seems a bit useless, but maybe...