Here's the way I see it...
The two tests that we normally test for which are ALT and AST are enzymes which normally reside within Liver Cells and are released by Damaged Liver Cells. So since there are billions of Liver Cells and since some Liver Cells are always in the process of dying. We always normally see some of these enzymes in the blood. So obviously we can't measure one liver cell dying out of billions. Just because some liver cells have died and been replaced by fatty tissue doesn't mean that cells are actively dying at this point. The enzymes represent active cells that are actively being damaged or dying not cells that have died in the past. So you can have Fatty Livers and normal Liver Function Tests, because the damage was done in the past. For example as you know Cardiac Enzymes are released during a Heart Attack and then are totally normal weeks or months later even though the Heart was seriously damaged.
It would be fun to meet you in person, couldn't we have great discussions.