>>23290623eh, "a lot" is debatable, it probably averages out to less than once per month, nothing totally outrageous.
Also, a "pairing" means something more than just collabing together. Like "AmeSame" shipperschizos deluding themselves into these girls having actual feelings for each other, or even fucking behind the scenes or whatever lunacy.
"AmeTori" feels a lot less serious than that (or maybe AmeTori shippers are just a lot less schizo about it than AmeSame fags were, and know it's all just playful harmless fun instead). Like, I don't doubt they're probably good friends, or at least can stand each other's company long enough to pretend, but there's certainly no serious feelings or whatever.
It's also mostly only Kiara who tries to put a "pair" label on it (and Ame more or less just passively indulges her, probably because she knows it's just harmless fun and Kiara doesn't mean anything deeper with it), but that's just because she tends to do that with everything (possibly because she thinks that the "branding" will her be more memorable or whatever), like Takamori, but she even gives her friend groups "brand names" like O'riends (Nene) or Holotori (the birds), etc. There's no need to read too much into it