Bartending Calories

I recently started a new job as a bartender. Up until yesterday I logged my shifts as 'cooking, food preparation'. Out of curiosity I decided to wear my HRM to work yesterday.

From 3-8 I cleaned toilets, took recycling out, restocked the bar and served happy hour customers. Not once was I without something to do, and I was not stood still for any longer than it takes to pour a pitcher. When i went for my break I checked my HRM and it said 1300 (or thereabouts).
I went back in at 9:30 and served the lively evening crowd. It wasn't hugely busy, being a Tuesday, but this is a popular bar and there is always something to do. At 12:30 we started closing up - my share of the work was dishwasher rotations, wiping surfaces, sweeping and mopping before carrying the recycling and empty kegs to the door for opening tomorrow.
In those 4 hours my HRM clocked up 1100.

Now I know a HRM isn't designed for use at rest - but at no point during my split was I resting. If it's acceptable to use a HRM when out for an easy walk, then surely nipping around behind a bar must be okay too.
I contemplated changing my activity level, but since some days I work 9 hours and some days I work none at all (and sit on the sofa all day) I thought I would log it separately for the time being.

Now if my BMR is 1440, which is almost 60 calories an hour, and I deducts 540 calories for the 9 hours I worked, I still come up with 1900. I finish work exhausted and hungry. My arms and legs are grateful to lie in bed and I can feel it in my muscles the next day.

Do you think I could have burned that many calories in a 9 hour bartending shift? Or shall I keep logging it as cooking (which estimates about 1050calories).

Please don't tell me to change my activity level, I will reconsider in a month or so when I am more accustomed to my new job.