I use 100 cal = 1 AP, and I usually earn about 50 a week. I eat either them or the WPAs, sometimes both. I don't understand not eating them at all--you're exercising, you need more calories. And one point is essentially 50 calories, so you're still burning more than you're eating.

I find that the activity calculator says I get way more APs than my HRM does, so I go by the HRM.