Turmoil I do not know the answer to your question "does this mean". But your battery will not overcharge short of failure ever. It will not undercharge through use short of failure ever.
If you are very concerned about battery life you should remove when plugged into AC. The charging is of little consequence in your scenario heat is a larger factor (and simply having fully charged [more later]) regarding battery longevity. But even as such not to the point I concern myself with.
You want to maximize your battery longevity? Remove with 40% to 50% charge store in cool place ie: fridge/freezer. That is not practical for me and I also think as qhn does use as UPS.
Tips:
You can't over charge the battery has a safety circuit that prevents.
You cannot under charge battery through usage, back to safety circuit. You can however run to it's minimum safe level. And with enough passage of time. The natural dissipation of charge you could fall below safe levels. But that just means don't run down and not charge for a month. Falling below safe levels will damage your battery.
The natural loss of charge I mentioned is why every few days even while on AC only you see battery topping off. This concerns you because limited number of charge cycles. Well let's say charges to 100% 3 days latter starts charging. Goes from 97% to 100%. Your Li-Ion is likely rated at 300-500 full cycles. So leaving plugged in you would lose 1 full cycle every 100 days at the end of the year you have used 3.65 of those 300-500. Not that big of an issue if you ask me.
I said heat is a bigger factor.
Here is a chart from battery U showing the comparison based on heat.
I do not accept the actual numbers in the chart but do accept the trends have validity.
