The effect on the SK epic seems to have some stacking issues.
Soul Consumption Recourse should stack with Vampiric curse recourse. -
http://lucy.alkabor.com/stacking_2466.html
http://lucy.alkabor.com/stacking_3977.html shows that the recourse doesn't stack when the detrimental effect of vampiric curse is on the caster, but the recourse should stack.