Steven.
Looking to your Video this sounds pretty normal to me. What is your expectation? When turning the jogwheel backwards that slow the sounds is moving back slow. That doesn't Sound different as in your Video.
The buffer size / latency has mainly to do with how fast the Sound is reacting on the movement of the Wheel. If there is a delay or not.
Not sure what others think, but for me this is normal and would be the same with any other gear.
In Addition what Format your Music is on? MP3 or other? The Frame rate of the Music would be interesting too. Just to make sure you are not using a compressed file Format of the Music which potentially sounds not so good when played that slow.