This is a bit of a half baked commentary because it's pretty short on details but I learned a couple of things recently that I haven't been able to test with any rigor yet. I figured I'd drop a note here in case someone wants to explore.

1. The deeplink URL syntax is way more variable than I thought. It is difficult to do (at least for my very rudimentary skills) but you can capture the AC deep link generation URL from Google flights. The syntax components in the link structure are quite a bit simpler than what power tools generates. Again, not a lot of testing but this structure seemed to have fewer issues where it wouldn't parse.

2. For the fare I happened to be looking at, Google flights was appending an authorization id that didn't seem to correspond to any active promo. It was also paired with some sort of agent id (that didn't seem to make much difference). From a cursory examination, this code wasn't a promo as much as it was the ability to access web fares that are normally visible on the AC site but are cheaper than published fares pulled by matrix. No idea if this was just that one fare or if it's more widespread.

I wish AC would make a deep link syntax guide available. I get why they don't other than to specific partners (or with an agreement or something) but it would be nice for my own use.