"Performed by" vs. "Also performed by" or "Featuring"

Does anyone know what logic roon is using to describe an artist at the work/part level as:

a) “performed by”
b) “also performed by”
c) “featuring”

In my library b) & c) pops up every now and then but it seems random and I cannot work out what the logic is or what I could tag to force those descriptors rather than the default a).

In a lot of cases because the default is to hide “album artists” on the work/part title lines roon then ends up describing secondary / accompanist artists as “performed by”. This is very confusing/misleading when it would be better to use “also performed by” and sometimes “featuring” instead.

After 4 years this appears to still be uncontrolled. Roon will bypass file tags whenever it feels it knows better. That is the logic, however manual over-ride is very sparse.

An example:

“Our Favorite Things” (erroneously given British “favourite” spelling, but fixed by preferring my file metadata)
Variously performed by Tony Bennett, Charlotte Church, Placido Domingo, Vanessa Williams

Roon shows each song as, “Also performed by” those people. It’s probably because it’s performed by those people. Roon knows each song is properly tagged with a Primary Artist(s) or Performer but ignores it.