Why in your theory doesn’t that happen for 1st and 2nd degree felonies?
Because longer sentences don’t have as much proportional variance as a shorter sentence.
When a sentencing range is 1-5 years, some people will have sentences that are 5 times as long as others. When the sentencing range is 25-40 years, nobody will have a sentence that is even twice the duration of someone else.
I understand the point you are trying to make on math. I am saying your point is based on flawed assumptions.
Yes, I am also saying that racism and sexism are the most likely explanation for any disproportionate outcome when looking at the legal system. Single judges might have their own personal variance, but when looking at state levels and above it always ends up being racism or sexism that drives the trends.