Our driving laws all differ dont they?
Cos for us, you get your (P's) licence at 17 - go on your opens when your 20
OR
Get your P's, stay on them for 3 years, then advance to your opens.
I don't know what WA laws state, but you're spose to be on your P's for 3 years here - so just check the numbers on his licence, because its possible u may have counted wrong, or he just lucked out didnt he.
You are off your P's three years to the date you got your P's - unless you have had your licence suspended in the meantime. Even then, you go on your Opens, just with less points.