First post to the forum but not new to BeerSmith! I only make 2.5 gallon batches and I'm using a 3 gallon cooler I purchased that has a valve attached. Have noticed that on my last couple of beers my efficiency has been in the upper 50's to low 60's, while BeerSmith projects 70 which is what I'm shooting for. My previous beers have all been relatively close to 70. Not sure what is happening. Two of the beers where high gravity beers; a Scottish Ale and a Christmas beer. However, I did a Kolsch recently and missed my preboil number 1.039 predicted, 1.023 actual. Mash for 60 minutes on all beers. Any advice would be appreciated!!