His numbers also accounted for the difference in starting stats - an Erudite has 32 INT more than an Iksar, assuming starting stats are distributed identically.
What I found most interesting about his posts were the calculations on how much mana the regen gave you over time.
Also, I just noticed this handy chart on the wiki:
http://wiki.project1999.org/Necroman...ksar:_Pre-Lich