Could you post an example of one of the posts where you experience the issue, so I can have a look?
If you want your site URL to remain private, you can also contact us via this form:
http://en.support.wordpress.com/contact/?jetpack=needs-service
It seems you have changed the look of the Jetpack buttons to match your own theme:
http://i.wpne.ws/MGZO
(it looks good, by the way!)
Since you use your own custom design, the sharing counts might not appear.
If you remove your customizations, do you still experience this issue?
I entered this URL in the button generator here, and it doesn’t seem like this URL was “+1’d” on Google+ yet.
If you did share it on Google+ it yourself, it seems that Google+ did not count it.
I am afraid there isn’t much I can do to help here. I would recommend that you report the count discrepancy to Google+ support team.
Thanks alot for your afford. I shared it privat in Google+. I try to share it public and see if this works. Sharing private in Facebook was no problem, it still counts.