The spell Life tap is suppose to by a 1 to 1 life to mana cost. At lvl1 the spell is suppose to cost warlocks 27 heal for 27 mana + spell power .
Also i dont think life tap is gotting the full spell power increase either https://wotlk-twinhead.twinstar.cz/?spell=1454
can some one please confirm if it was changed
My ranks say a different amount on lorderon
rank 1: 134 - 68 (27-27)
rank 2: 173 - 115 (66-66)
rank 3: 239 - 194 (132-132)
and i have inproved life tap 20% mana award
Check your combat log to see how much mana you are actually getting for the specified health cost. The tooltip may not necessarily be accurate and should never be treated as such.