I'm not sure about that as I'm using my Surface Pro for a solid 8-10 hours a day right now but it is only on charge around 4-5 hours. If I go with this dock it will be getting some type of charge all 8-10 hours. Over the course of a year that might make a difference.
What you describe of overcharging has generally not been a problem for about a decade at least... or you are talking about what I'm going to call "microcharging" where, as a battery sits in a device, it discharges a tiny bit over time which will then be recharged, thus inducing many many tiny recharges which add up to many full charge cycles which degrades your battery over a year. This is what kills laptop batteries if you are almost always plugged in but leave your battery in, thus the recommendation that you remove your laptop battery if you don't need it. I should note that what kills batteries these days is, basically, how much your battery has been charged, often referred to as full charge cycles.
This advice changes, however, when you cannot remove the battery. If you cannot remove the battery, it is better to have this microcharging happening rather than ACTUALLY draining the battery by running off of it since you will go through far more full charge cycles by constantly using your battery all day, thus degrade it faster. This is why it is recommended that, if you can, always plug in your phones or ultrabooks/tablets since that will actually extend the life of your battery due to less full charge cycles.
Some basic information about lithium ion batteries can be found here:
https://www.apple.com/ca/batteries/
I should also mention that there is no memory effect with lithium ion, thus it is always better to have it charging while using. There can be some subtlety to this (eg. the battery works most optimally at some value, possibly between 50-60% charged I think, and at some temperature) but, for most people, just leaving it plugged in when you're using it as a rule is basically optimal.
