Do you hear the climate compressor in the interior ?

Hello everyone,
After my air conditioning system has been decreasing in performance over the last few years, I had new refrigerant (R409A) filled in today.
The facility has been evacuated.
This is shown next to R 413A as Drop In for R12.
The cooling works again great, I have had 7°C air outlet temperature today (37°C outside).
What worries me, however, is the fact that the current compressor is first of all noticed by the lower drive power of the car.
Another point is a noticeable dull roaring in the interior that stops immediately when you shut down the compressor.
Can it be, to my reassurance, that I am no longer used to it, as it is when the climate brings full performance, or is there something in the bush?
By the way:
AUDI originally had 1100 g R12 in it.
After conversion to R 134A, it should be 900g.
(Info from the VAG farm)
We filled in 750g R409A today, as a precautionary measure.

greetings
Jürgen