Extra Effort Costs for Psionic Powers - pls help

[malloyd]

Originally Posted by Thökk

I don't get how it was calculated that extra effort from 4 to 5 here costs 25%.

Can somebody clarify this rule to me, please.

P.S. How do I calculate extra effort to get from 1 to 5? From 4 to 9? Can you walk me through it?

It works on the numerical levels, which Psionic Powers happen to use, though most of GURPS does not. You calculate it as 100% (higher/lower -1), so 5 is 1.25 (125%) x 4, or a 25% increase. 5 is 5.00 (500%) x 1, or a 400% increase. 9 is 2.25 x 4, or a 125% increase.