Question about heart rate monitor?

I have a Polar F4 and I am curious about the calorie burn numbers. I just got a it recently so I have been experimenting with it to see what it does. One day I sat in the sunshine reading with it on to see what it did, I obviously use it when working out or riding... but the other day I threw it on when we went to a parade to see what would happen. I set it when we left the house and we walked a block or two to get to the parade route, then we stood around watching. I was either standing still or standing swaying a 20 pound baby. Then we went for about a mile walk to get some breakfast then a mile home.

When I got home I checked what it said and it said 411. WHAT? That can't be right, I only walked two miles and it was pretty leisurely. But it was spread out over a while and much of it was just standing around. So my question is this:

When using a Polar monitor, does the calorie burned number INCLUDE your BMR or is that subtracted out? For example, if it says I burned 411 calories over about a two hour period and my BMR for that same period is about 144, should I subtract that from the 411 and add the difference (267) to my diary or is that already done by the HRM? I have my activity level set to sedentary so I do like to add walks and stuff but I don't want to grossly overstate what I'm burning.

Also, I'm trying not to obsess over numbers and such and as you can see, it's not working.