Interesting, and if that rings true they should update their support doc.
Any chance you can look into this @ZackeryWeimer?
ETA: I will note that those answers are from a year ago and could be incorrect at this time. I say that because they have swapped the 10 indoor TR workout requirement on/off a time or two since AIFTPD was introduced. It had to do with undesired results as shown by several users here on the forum at the very least.
With that in mind, I am personally skeptical that pure HR data (no power data) can really be useful in the AIFTPD context. But I welcome clarity one way or the other from TR reps.