consistency/efficiency problems

Hey all. I sure hope someone here can point me in the right direction on this. So heres the issue. I started all grain a few months back after doing several PM, and a few small batch all grain trial runs. My first AG I had a brew house of 76%:rockin: Not bad I thought since this was all new equipment and what not. The next batch netted me a BH of 72%, still not to bad, but this is the point where I started to notice a bad trend. Every single batch I brew (no mater what the style) my BH has gone down a few points. I do the same steps every single time as I'm trying to be consistent, even ant the expense of efficiency. But no mater what its alway lower that the last batch. With the batch I just brewed today, I had my BH set at 62% and ended up with 54% could this just be a crush issue? I have all my grain crushed at my LHBS, so I really dont have any control over that. (SWMBO is getting me a BC for my B-day) But till that gets here any thoughts? Suggestions? Anything!?

how are you figuring your eff? do you use software or online calc? if software and you are resetting your brewhouse eff each brew then my guess is that the software is reducing your grain a little each reset. try keeping the brewhouse eff the same so it calculates grain the same for each batch( the software is changing your consistency so you are unknowingly not being consistent)
I think I'm thinking this through right.

In efficiency, two most important factors are:
1. how fine is grain crush
2. sparging

So, tell us, how do you do the sparging.

Did you buy all the grain at once or is each batch a separate purchase?

how are you storing your grain? Is there a chance it's taking on humidity? Is so, it could affect your mash efficiency and also your grain measuring. If your new grain is 5% moisture and that goes up to 10 - 12% during storage then you're going to have 7% less grain for the same weight and that'll affect your efficiency by itself. you can also assume that the staling of the grain will affect your mash efficiency as well.

Sorry I left out a few thing, was in a hurry to get out of the house this morning.

I use Beer Smith. Each time I redid my BH numbers, I would up the grain bill to get me to the SG I was after. I batch sparge in 2 equal sized rounds with 175* water. So a normal sparge would go like this:

After rest, recirculate and drain
Add sparge water, stir vigorously, recirculate and drain
Add sparge water, stir vigorously, recirculate, drain, begin boil.

As for the grain. I email my order in the night before and pick up the grain the day I brew. To small a house to store grain in