I reread the text in the book and you might be right, i misread it.
the magister is not affected by psychic phenomena, unless it's perils of the warp. perils of the warp affect him like any normal psycher.
so my current interpretation is:
when rolling on the psychic phenomena table, the magister is immune to effect 1-74, although others might still be affected.
he has the possibility to reroll on the 6.2 table if he dislikes the result ( result of 75+ by example) OR decide who is affected by the result rolled by spending an infamy point.
apparently the perils of the warp table is never referenced in the magisters text. so if he rolls a 65+ ( for a result of 75) he cannot burn an infamy point to decide who is affected, he either spends an infamy point to reroll, or takes his chances on the perils of the warp table ( 6.3) and cannot change anything.
This means that he can burn an infamy point in 64% of the cases ,if he is not sustaining any power, to have his enemies be affected by the result he rolled on table 6.2. ( and if what i read on the fora is correct,most psychers have at least one ongoing affect they are maintaining in combat, further adding a +10 to his rolls, meaning 46 %chance of perils in which case he can spend an infamy point to reroll, having again 46% chance of perils).
the warplock talent lets you ignore a result on the 6.2 table, you have to pay for it with d5 wounds and no powers for 1 round, but ignore is 36+% better better then rerolling, since the reroll has 36+% chance of being perils of the warp ( which has effects worse then d5 wounds and not being able to use psychic powers for 1 turn). It also does not require an infamypoint.
I know that we have different opinions on the price of an infamypoint, i think this is a high price, but i have only recently started playing and have only got 2 infamypoints available atm . towards the end of the story i can see that having 6-8 infamypoints per session gives more leeway in the usage of those infamypoints, but i assume that at that point you encounter more dangerous situations and will need more infamypoints to stay alive.
While it might be somewhat powerfull to be able to affect your enemies with result 11-74 of the 6.2 table, you are not really sure what you will get, and have a high chance of getting hit yourself by table 6.3 which is alot worse, oh sure you can reroll, but have a 36% of getting hit by the 6.3 tabel anyways.
the "usable" effect on table 6.2 are not that many,
18-20 forget something trivial( borderline usefull)
33-35 no run or charge actions
36-38 Gain fear1 for 1 round and 1 corruptionpoint
42-44 Ag+30 test or be knocked down
48-50 Ag+10 test or be knocked down
54-56 test against fear 1
57-59 D10 meter falling damage
60-62 T-test or be deafened ( marginally usefull)
63-65 knocked down, d5-T wounds and fear2 test
66-68 WP-10 or gain d5 corruption
69-71 ranged weapons jam
72-74 frenzy for a round an WP-10 or suffer d5 corruption
for a total of 39 of "usefull results", 25 "useless" but cinematic results, and 36 Perils of the warpif he is not sustaining powers.
compared to a nightlord who can spend infamypoints to get a fear rating up to 4 for an entire session i don't thin kit's that broken.
But i do agree that he must choose to reroll on the table 6.2 before rolling on table 6.3 if he would have a result of 75+ on table 6.2. And i am convinced that he cannot choose targets for table 6.3.