Mixer Keyframe writing to have an averaging mode
When writing keyframes in clip mode (especially using a control surface) you are listening and making adjiustments on the fly. The keyframes written are literally hundreds of adjustments written in just a couple of seconds and are usually being made as a reaction to hearing a peak and the peak is always missed. (Human reaction time) Editing the keyframes is painful and that many keyframes are not needed. This area of working mix levels needs attention. Both in clip and track mixing modes. Again, try this with an external control surface to see how poorly it works.
Sven Brencher commented
You can go to Preferences > Audio and change how often Premiere Pro should create Keyframes (simply extend the Milliseconds value to something that makes sense for you).