Ok, stupid question but are you checking the fluid level with the engine running?
You should be checking it with the fluid warm not hot, engine idling, in park, on a level surface.
I checked with the engine off, I checked with it idling and cold, I checked with it idling and warm (but it seems to be overheating) and always in park on a reasonably level surface. The last time I checked it and it was super low, it was warm, running and parked on a level surface. This time, engine warm, rowed the gears, drove a bit, idling and parked, after 1 bottle of lucas and maybe 200ml of atf, it was high.