*coughs* To answer the original question:
For the base stats (int, will, strength, etc), it works in bands of ten. Take whatever band of ten you're in (eg, 120-129, I'd consider the 12th lot of ten) and add 10 to that, and you need that many PPs to train a level in that stat.
Examples! (Can you teach I tutor mathematics?

)
Strength 120: 12+10=22PPs to train a level.
Will 87: 8+10=18PPs to train a level.
Endurance 199: 19+10=29PPs to train a level.
So supposing you were daft as a brick, intelligence 0 (or ugly as a brick, charisma 0) to train all the way up to 200 would cost 10*(10+11+12+...+28+29)=3900PPs.
I've been trying to work out the mathematical formula behind the other skills. It looked linear for a while, but there seems to be a power-factor involved somewhere. Work is continuing ^_^
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