no difference between 1, 2 or 29 points in it.
i literally just tried it and am sure

in midgame you get def for sure.
so because of this i suggest the following:
Max: Embalming,Deathward, Parasite, (this gives a lot of defense to death pact), Death Pact (this gives you damage, which is the most important PLUS def with every point).
1-7Points: Carnage.
1 Point: Talon's Hold . (we prolly get a little slow from and item and you need just 25 [right?], so 1 point gives you 13 which is nice
1 Point: Graveyard
1 Point: Rhatma's Chosen (I think you get max attack speed easily from equip, so is 1% DS worth a skill point?
Rest: my idea would be to split between dragonfire oil and famine. Both would give you additional DEF via death pact, and you can decide if you want additional fire dmg or ias+run speed.
I would not waste points in Blood Skeleton or Nightwalker, since you can get famine points for it..
ALSO Whats your source on the breakpoints? I have no idea where you go those from..