My Intelligence is at 5

I started off an earned 13 points at level 2
at level 3 12 points
level 4 got 13 points and chose the education perk which earns you a bonus of 2 extra point per level up
at level 5 I was given 14 points when I should have gotten 15 points

I'm not even sure if 13 was supposed to the default for INT 5 to begin with I could of sworn 15 is the standard thus if had 10 INT you get 20 points per level up with eduction perk 22 total

I'm on the Xbox 360 console

Skill points are distributed each level at 10+(0.5xIntelligence). So at each other level you get those half points you might have if you have an odd Intelligence stat added together.

Certain skill levels give for example 12.5 points so it rounds up and you get 12 on one level up but will get 13 on the next. So you aren't losing out on points so don't worry.

So they changed it I see

FO3 was straight forward depending on INT and the eduction perk always giving you the same skill point each level etc.

Did the change it for balance cause the level cap being now higher the 20 which it is 28 I think now for NV?

The level cap is 30. They changed it so you couldn't become an unstoppable force.