Heart rate way low on treadmill-Versa

[Roboz85]

So I have noticed that when i use a stationary bike at the gym my Versa reads the heart rate extremely close to the heart rate monitors on the bike. Conversely when I use the treadmill, my versa actually reads about 30-40 BPMs lower than the palm monitors on the treadmill. Is it the exercise option i choose? should i just use the spinning function and not use the treadmill one? I only care because I'm tracking calories in through Fitbit. So id like to get a relatively close reading of calories burned. I have read in other forums that people have been getting high readings on their Versa but not many saying theirs is reading lower with the exception of my father in law. Thanks in advance.

Moderator edit: added label

Moderator edit: updated subject for clarity

[Marrrmaduke]

@Roboz85 I would say it's nothing unusual, but I won't until you give me some numbers. Each time I would do bike the HR was pretty close as well, but on handles of elliptical... hohoho sometimes 60 sometimes 200...