That must have been a long run!
I trust my HR monitor (lol...when it is working perfectly, that is). I've started keeping track of how far the Polar and Precor are from each other, and the longer my walk/jog is, the further apart they get. If I'm up in the high 700 range on the Polar monitor, the treadmill is telling me 400 something. I'm not sure I've ever hit much higher than 800, but I bet if I hit 1200 on my monitor it would be about the same as what you saw on the treadmill.
If you eat those calories or Points or however you're looking at it, even though I would trust my HR monitor, I probably wouldn't, probably *couldn't*, eat ALL of that. (of course with Points you're not eating all of the calories right back, it ends up being about half)
I do weight watchers, so this won't work for you if you do not.....what I would do, and this has gotten more accurate (I think) as I get into better shape and my resting and working pulse have come down a bit (though my pulse is higher than average and ALWAYS has been), is to put it through the "etools" tracker; jogging for x minutes, walking for y minutes, and see what that says. The more in shape I get, the better it matches up to my "wow that's high" HR monitor finding.
But that last paragraph is only useful if you do WW.
If you're upping your food intake to help make up for that big energy burn, maybe let your hunger today and tomorrow be your guide, but make really good choices so that you are making up for the energy being burned, not just taking in empty calories.