Actually, his graph is just different from what he says. He thinks exp should increase exponentially and exp/h increase at a slightly lower exponential rate. More importantly, having a linear increase in the time it takes to level up. And honestly, I'll keep repeating this, there's at least 5 years of work to do before you can think about 120 skills. Revamp all skills so that they're useful, set up a baseline for exp/h and implement it in all skills. This baseline will include a semi-afk method and a faster click-intensive method.