Visitor count not matching between getclicky and piwik?

Hi I installed a few weeks ago and have been matching my tracking with getclicky, it seems that getclicky has between 10 -15 more visitor counts than piwik. I am looking to dump getclicky but want to make sure piwik is accurate. Anyone know why this would be happening? I have the tracking code on all my pages and IPB forum. Any ideas would be helpful. Thanks