This is the level in my current C5 and is the same as the previous one, on normal height.
I can only presume that this is correct although there is some conflicting advice with regard to the levels and the height they should be checked at.
Found the number on the drivers door shut, topped up to the lower cut outs at bottom of filler neck. Took approx 750ml to get the level correct, put cap back on and all works fine.
Was worried the suspension would not work due to letting the pressure out of the system.