You are basically asking if you need to calibrate the battery and I've heard answers on both side about that so I agree go with what the maker says.
What kind of laptop is it? Dell has a special feature called Desktop-mode battery charge. What it does is if your laptop is plugged in for some many hours it will automatically adjust the charge levels of the battery. The adjustments include regularly allowing the battery to discharge, even while plugged in. The benefits help slow the reduction of charge capacity over time and may even decrease the need to purchase a replacement battery during the life of your laptop.
I have an Alienware and awhile back i noticed my i was plugged in and the battery was discharging while plugged in and finally went to 0 and turned off and wouldn['t turn on. I called Dell and it turned out to be the mobo which was replaced under warranty. So typically when it goes into this Desk-top mode it would say 95% but go no lower and act like it was charging and would remain that way for a couple of days. Yesterday it said 75% and I was concerned but it stayed at 75% so I knew the Desktop mode was working. Dell says it will increase the life of the battery. Well I had a HP battery once die right after the warranty was up.