Hold on - are you using the same Ace stone that's in the top right in this picture?
Attachment 112437
Because if you are... I don't know, but I don't know how guys use that to hone their blades to shave ready status! I am sure they do but I use mine as a bevel setter - pre-Nani 1K.
In spite of me not being able to use it as a finisher - have you checked to see if it's flat? Mine has to go down in the annals of most difficult to lap... ever. Lets just say it had ambitions to be a circle. :) Kind of makes it hard to learn on.