I envy/miss that kind of consistency. I used to be dialed in - knew I was at about 78%. With BeerSmith, I could get my target OG almost dead on. Since we moved, I have started using Brun'n Water. Slightly better water and being more mindful of water chemistry has boosted me up to around 85%, but what is vexing me is the loss of consistency. My efficiency jumps around almost 10 points over the last half dozen or so batches. I'm thinking the culprit has to be the water chemistry, but what precisely it is, I can't nail down. I just got 92% on my last batch, but I was planning for 83! I would gladly go back to 78 if I knew I could keep it!