Is this 'channeled' or is it instant like other warlock curses? The 3200 / 60 isnt correct in the sense that the 3200 counts, and then any other damage / nukes / dots put on the thing during that minute while waiting for the timer count, not to mention damage done by pet ...
reather use CoA then this lol or like previously said CoE or CoS due to the fact that you are gambling on weather the mob will live for 1 minute not to mention gambling on whether you will have a level 60 doomguard breathing down your neck in a minute also lol