The Series 10 and 11 machines have three level fill points the Series 12 and above have two level fill points.
I know Bulky Items wash selection will give you a High water fill which is only 7 inches or so of water in the wash basket. 3.5 inches of water for a medium fill.
You can turn on/open the water inlet valves in Service Mode but I would not recommend that. A manual fill as you did is the only safe way to set the additional water level IMOP.
FAV6800A/FAV9800A Service Manual for reference.