If you did this test as Sacrifice specced, did you take into account the dot that CB now leaves behind? cause that's supposed to be in that neighbourhood of amount of damage.
Speaking from experience, it's been like that since 5.1 when they turned the damage from sacrifice into a dot.
On a side note, you realise some speces have a passive damage reduction right?
Did you take into account procs and if you had the same ones in both cases? What class did you test it on? Remember that damage does fluctuate and your sample is pretty small.