Very interesting content. Thank you.
Intuitively, there seems to have been more fluctuations than usual after the plunge in STEEM prices.
In my memory, there is usually a change between 17th and 22nd, and sometimes one or two TOP witnesses seem to change.
Other big fluctuations seem to be rare. The long-term influence of top-witnesses, the strong influence of freedom and blocktrades accounts seems to be the main reason, and mutual voting among top-witnesses seems to work partly.
Stability of witness status is an important factor in job performance, but since their term is not fixed, more active ranking changes seem desirable.