Hi, PCviola.
I can recall Hanneke talking about a reverse waterfall a couple of times in tune tutorials…she doesn’t cover that in the waterfall technique lesson, but occasionally she will adapt that technique to end up on a different note.
You might run into folks who would consider that non-Trad, but Scottish fiddling is still a living language…the folks who are willing to bend the rules get to define the new norm! My thoughts are that if it enhances the tune for you, who cares whether or not it’s considered “acceptable”
My 2c…