Yeah, in my unscientific perusal of the various flats threads my general conclusion is that they work best on P basses, less so on Jazz variants, but with plenty of exceptions. I did not like them on my Jazz, but I also don't really care for an overtly favored midrange in my tone, so it's possible I wouldn't care for them on any kind of bass.
I've used them on P-basses and hollow body basses with success, but yeah like you jazz basses are hit and miss for me with TIs.