This proof is from LuckyLady Llewellyn.
Plum Tipped Black whisker color is dominant to Butterscotch Tipped Black.
It's a bit complex because Plum Tipped Black whiskers exist on both sides of the pedigree and one side doesn't have much recessive whisker information apparent - but once we get to the second pedigree that clears up.
Lenore shows the Plum Tipped whisker and hides the Butterscotch Black, and on the kitten the Butterscotch Black has been pulled out from under the Plum by.... what? Are we sure that Lenore hides the Butterscotch Black and that it didn't come from the other side?
In the second pedigree we can see that Feliz hides the Grey Tipped Black or more recessive and so the Butterscotch Tipped Black whisker MUST have come out from under the Plum Tipped Whisker.