This is great! I wasn't able to find the posts I was looking for, but I did find one post from the account in question, so I think the tool is working just fine and something works differently than I expected.
Discussion
Oh, I found some additional notes after clicking all the different kinds in my query. I still didn't find the ones I was looking for.
The software that I'm investigating must be using multiple accounts so there is better privacy. Clever.
It doesn't show all of the kinds. Not all kinds have a merged NIP.