Broader Searches Give Me Fewer Results with the Ancestry.com Slider

If I'm doing something wrong, please inform me.

The broader a search is, the more results one should obtain. That's a basic premise of database searching.

If you want more results, make your more broad.

That's not what is happening for me at least on this search with the sliders at Ancestry.com

This search screen shows that obtained 194 results for my search of the 1900 census for John Coffmann as shown below--the last name is set to the second slider from the left.

I then broadened my search by moving the slider to the left.

Except I got 155 matches. Shouldn't there be more?

Am I doing something wrong?

Can anyone else replicate these searches?

I'd like to know what I'm not doing correct or what I am not understanding correctly.