yes If you are brewing say a "5 gallon batch" in the 20 gallon system and shooting for an 8% beer or something like that the grain bill would most likely be above the water. Not sure about a 10 gallon batch. Honestly I don't brew beers that big anymore. Also I always brew 7 gallons or better even if I am only brewing a five gallon batch just as a preventative but mostly I brew 10 gallons in which case I brew an 11 gallon batch and do so to account for losses for dumping tasting etc.Thanks! That's good to know that CBS fixed some issues and that the newer systems don't have the same problems. I think another issue the individual who reported under 70% might be having is less than a full capacity batch. HIs attachment indicated he was only putting 12 gallons into the fermenter with a half barrel system. With the smaller batch there's a considerable percentage of his mash liquid under the basket. Not sure if that could be impacting his efficiency issues.
Regarding higher ABV beers, what is the issue there? Too tall of a grain bed?