Stat caps.

I don't think you understood my meaning. If Slath wanted to make a 1st level spell and he had 65% spellcraft, you'd give him a straight roll. Then when he had a 150% spellcraft and wanted to make that same 1st level spell, you'd give him a -80%. -That's not an exact example, it's just similar to what happened. Buying higher and higher didn't always help with the easy stuff.

I am just saying the same task should always require the same level of difficulty. -They shouldn't slide relative to your new skill level.