I also use my Garmin's calories burned number for tracking. It is usually quite a bit higher than Spark's number. I don't think it matters as long as you are consistent and use the same method all the time.
Then you can know your net calorie need in order to lose a pound or so a week.
Calories Consumed - Calories Burned leaves your Net Calories
What number does this have to be for consistent weight loss or maintenance.
"It's not how old you are, it's how you are old."
"I am still learning." Michelangelo
| Pounds lost: 2.5