PowerDock 2 - Discharge / Charge

[cas]

I've been logging my PD2 battery level over the last couple of days, as reported by the /usr/bin/power-dock2 utility and observed an interesting discharge/charge trend:

Voltage discharges to around 4v and then charges up to 4.12v repeatedly.
Has anyone else observed the same thing?
Is this normal?
I would assume that this is handled by the battery management chip. Or am I wrong?

Is it odd that this interests me? ;-D