Suppose I have a FLAC music file and I convert it to let’s say 192 kbps mp3 and then I use this 192 kbps file as a base and create another conversion to 160 kbps.
Not supose I take the source Flac file again and convert directly to 160 kbps.
Do both 160 kbps files have the same quality?
It is called generation loss. https://www.thewelltemperedcomputer.com/KB/Generation.htm
With each lossy compression cycle you add more loss.
The remedy is called transcoding. You have your audio files in a lossless format and you convert them on the fly to a lossy format to save space for use on e.g. a mobile.