So, I only had one 5k time (22:44) and one 10k time (47:35) from last fall prior to starting the Hansons training, and when I used the McMillan calculator, it estimated between 1:45:15 (based on 5k) and 1:46:05 (based on 10k) for the half marathon. As I have gotten older, I've noticed the pattern that I seem to perform relatively better on the shorter distances when looking at the equivalent times tables but not as well on the longer distances (BTW, I think this was the opposite when I was younger). So, I figured those equivalent times were probably not really achievable at that time. But I was sold on the Hansons plan, so I thought maybe, with the right training, I could get closer to the equivalent times tables with a half marathon. Also, although it was two and a half years ago, I did run a 1:49 half, so I thought if I am in better shape (which I thought I should be after the Hansons plan), then 1:45 didn't seem out of reach and somewhat inline with the equivalent times calculators. Plus, it was a nice round number, both from a 1:45:00 total time and 8:00 pace perspective. I know, not a reason to decide, but overall, I felt is was in the right range of what I could accomplish.
No, the 2:04 was not my POT, that was just a half marathon I ran when I was helping pace a friend, and the Disney tracking site (XACT) just lists other runs that you did in the past where XACT was used for tracking. I do not think you can see the submitted POTs anywhere. My submitted POT was a 10k (46:49) from almost two years ago.