Power and Vests: What is the Difference?

I recently clicked on "Power Down" and apparently it kicked in. That's okay, since I'll probably just re-invest it with a Power Up. (I now see that I can cancel it if I wish, so that's good there is such an option.) My question is: When I click on "Transfers", it shows how many "Vests" I have for the Power Down, but this is a higher number than my current "Power" balance. When I click on my username to view my account, I see only the "Power" number; the "Vests" number does not appear unless I look at transfers. Can anyone help me understand what I am looking at and why these numbers are so different? Thanks.