Tradeskill Skill Up Formula

[Bidoof]

Sorry if this has been answered somewhere already and I missed it; my search skills are weak.

In the tradeskill section of the wiki, it lists the formulas for successful combines. I'm wondering if anyone can tell me the formula(s) for getting skill ups on tradeskill combines. I know most (if not all) tradeskills have a guide for getting skill ups, but I like seeing numbers and such, maybe even make a pointless excel sheet of it.

I couldn't find a p1999 answer to this in my searching. I did find this from 2004 on EQ Traders Corner about Live's formulas:
http://mboards.eqtraders.com/eq/show...killup-formula
Is this tiered two-check system also used here?

Thanks for any insight.