I'm trying to wrap my head around the delay coverage when it combines with all these Future Flight Credits I'm accumulating (in the context of United flights, no more change fees, and the flight prices continuing to drop lately).

(1) It seems clear that even if I buy most of the flight with credits, so long as I buy a little bit of it with the Chase card, I'm covered. Great.

(2) Then if I do 'change flight' and end up with a residual, it's not clear which original payment is getting converted to the residual, but it seems plausible that my flight is still tagged internally as 'paid for with Chase card'? And that's true for repeated changes, since the flight always costs *something*, so we can imagine the last dollar is still Chase's dollar?

(3) Whereas if I cancel the flight and apply the credit to a new flight, I bet that new flight loses that internal tag, and I'm not covered? (Even though I never got any money back, so the Chase money obviously went *somewhere*, I expect I'll have a tough time convincing them that it went to this new flight.) So in that scenario, my safest option would be to spend a little bit new on the Chase card.

(4) And with that in mind, if I have an expensive flight I want to cancel, my best bet rather than getting one huge credit is to change-flight it several times to a progressively cheaper flight, so I end up with manageable-size residuals to recombine with small Chase payments over the next year, so everything counts as covered?

I accept that I might be overoptimizing here, but if I can't do that on Flyertalk, where can I do it.