We are usually meeting spending requirements on multiple cards, so I'll send her $550, $300 and $142.37 or some such random amounts. But I doubt it really matters. Some months we have sent $1000 back and forth, one payment each.

Nothing has changed with AP except that they have made it more difficult to set up multiple accounts per person. Amazon is clearly ok with paying the CC fees on our transfers, probably because it drives traffic and ad revenue to their sites. Just Do It - Virtually every question in here is way overthinking.