For many li-ion laptop batteries, the manufacturer's configuration of a 100 % charge is pretty much equivalent to overcharging. I've seen many laptops over the years with swollen batteries, almost all of them had been plugged in all the time, with the battery kept at 100 % charge.
As an electrical engineer you should know that technically there is no 100 % charge for batteries. A battery can more or less safely be charged up to to a certain voltage. The 100 % charge point is something the manufacturer can choose (of course within limits depending on cell chemistry). A manufacturer can choose a higher cell voltage than another to gain a little more capacity, at the cost of longterm reliability. There are manufacturers that choose a cell voltage of 4250 mV and while that's possible and works okay if charged only occasionally, if plugged in all the time, this pretty much ensures killing the batteries rather quickly. I would certainly call that overcharging.
Since you already mentioned charging thresholds, I just want to say, anyone considering using a laptop as a server should absolutely make use of this feature and limit the maximum charge.