Mines done around 0.75l in 7k.
I just check it every two weeks. If it needs topping up I top it up.
I own a pressure tester. I can't see obvious signs of a leak.
I do not agree coolant should be lost as it's a sealed system but I understand the level will raise when hot and cold.
Still I hope I don't have any issues as my remap is booked next week so bye bye warranty.
Call Audi breakdown (get an Audi technician in a van) there is a software update, and they vent the system at the same time, had mine done and no problems since. Not had to top up