glug111

Hi everyone, help requiredif possible.
I have an A5 Coupe 2.0 TFSI 2010 model. There is no oil dipstick only a bar chart reading on the dashboard of Max and Minimum levels.
Once when the level indicated just below half way to Minimum an indicator light came on saying " Add 1 ltr of oil".
Since I added the oil it went back up to Maximum.
After a number of miles the level has dropped and it got to belowe the Minimum, nothing on the bar chart but the light never came back on to say add some oil.
I contacted our local Audi dealer and spoke to their technician who said that the level had to get below Minimum to set off the light indicating to add some oil. This is what I found a little strange.
Can anyone confirm this is correct or do I have a faulty low level switch.
As a check I bought a dipstick, set it at 39 and the oil level reading was 5.