For +75% XP skill boost in Occupation and Traits selectiong menu you getting +300% XP boost in game.
For +100% XP skill boost in Occupation and Traits selectiong menu you getting +433% XP boost in game.
For +125% XP skill boost in Occupation and Traits selectiong menu you getting +566% XP boost in game.
So it's look's like some one set up XP boost multiplier wrongly, from 0,25 to 1,33
If we will calculate it:
0,25 intesd of 1,33 will be:
(0,75/0,25)*1,33=4 with is mean +300%
(1/0,25)*1,33=5,33 with is mean +433%
(1,25/0,25)*1,33=6,66 with is mean +566%
I'm russian, and I'm not so good on english, but this is language of math, you have to understand what I'm talking about.
Right?
BTW
Fast learner and slow learner works fine +30% XP and -30% XP
So problem with only skills where you have personal boost from 75% to 125% only.
P/S
I'm not set up sand box where you can set up XP boost multiplier, to 1000. It's for XP = 1 so I know it's wrong and you have to know about it.