I think you need to manually adjust the length of the audio stream after you extracted it, they are usually of the common fixed sample rates (like 44.1kHz or 48kHz) and are not tied to the frame rate of the video stream (other than being the same length in time).

For such a small percentage change (a few seconds over something like an hour long) "Change Speed" in an audio editor should be good enough, the shift in pitch should not be noticeable.

https://www.youtube.com/watch?v=pkPF8uN0bE8