I don’t know much about running power meters, but from what I’ve read they are indirect measures of output. Less reliable than a bike or rowing power meter. On flat ground, pace is probably a better metric.
It sounds as though the wind affected your first test, to the point that it’s not going to give you good data on your aerobic threshold. So, if you throw out that test, you have two data points suggesting that you can hold a 145bpm, 5:10/min pace at or below aerobic threshold. I assume that’s 5 minutes per kilometer, not per mile. 🙂
150bpm for your AeT sounds like a reasonable assessment. If you want to be conservative, set the top of your Zone 1 at something like 135bpm, and accumulate time in Z1.