Hi People

I have a question regarding the A/C control. As I open it, let's say I put it at 20 degree Celcius, the fan should keep running till the inside temperature reaches 20 degree, right? But I notice that the heat keep coming out at high level no matter how long I had opened it, same as I just start it. Does it have a problem? Because I have an Audi at home, and the automatic climate control will lower the quantity of heat coming out as it reaches the temperature. Does anyone have similar problem or any comment about this issue?

Any input would be appreciated, THANK A LOT