Estimated discount drops for no apprent reason

This morning (March 2) my father's estimated discount dropped from 25% to 22.5% for no apparent reason.

My father's driving stats are still better than mine but he has the lower discount now.

Why?

He has less daily driving
He has fewer braking incidents
He has less driving in the medium and high risk times
He has lower high speed
yet his discount dropped

For comparison, here are my stats.
The only place where mine are better is that I have more driving in the very low time period

Update March 3

This morning my estimate discount also dropped even though my stats have improved

My km per day dropped from 9.25 to 9.21.
My percentage driving in the medium risk times dropped from 10.26% to 10.2%.
There have been no speeding or braking events.

This makes no sense