It looks like the PvP spell damage was 66% from every reasonable source I can find, eg:
Plus the math on those ratios up above lines up with 66%, even the Demi Lich hp values (ie, 32/48 = 0.666) . I have no idea what those numpties on Alla were talking about.
Depending on how P99 does its mechanics (is Lich self-damage on P99 being affected by PvP reduction code on Blue?), either the Lich line HP costs should be raised as above (ie, revert the 2006 changes on Lucy), or the HP cost should simply be raised temporarily then lowered back down in September 1999 to reflect what they would become after the PvP spell damage reduction was implemented.
This thread is now named strangely so mods feel free to rename it to "Necromancer Lich line should cost more HP until September 1999 patch era" or similar.