goschman, my efficiency varied too depending where I bought the crushed grain. Owner of a LHBS let me mic his mill, turned out to be .055. It prevents stuck sparges but kills efficiency.
Instead of brewing to see where your efficiency is, see if the LHBS will let you mic their mill. If you have a couple of LHBS to choose from pick the one with the smallest setting, assuming it is not too narrow to give a stuck sparge.
Thanks for the idea. I guess the best solution would be to get my own mill and do it at home. I don't see this happening any time soon.
I will be getting grains from this same shop where I got higher efficicency for my next batch. I will try to remember to report back what my results are though my grist will be different. I have been too lazy to dive into pH and water chemistry so I am hoping most of my efficiency inconsisteny issues are indeed tied to the crush.