Generally, it's normal to see fluctuations in your sub count because we want to make sure the numbers are 100% accurate, so we perform additional verification & spam reviews. Also, it's likely folks are subscribing & unsubscribing as well. More info: https://goo.gl/6B1Eb6
Different pages across YouTube (such as the logged in homepage, search & watch pages) are updated at different intervals. It is a common occurrence that the total sub count for the same channel may vary. Hope this clarify.