The Android API allows you do get the voltage and current of the battery (with negative current for discharging and positive for charging), so there are apps out there that tell you the real state of the battery when it's in that range. The phones will tell the user fully charged before it's actually completely charged, but it's not much. It's mainly so if you leave it plugged in, it can cycle a bit up and down while still displaying 100% instead of continually trickle-charging.
My guess is tablets would be similar, but I've never had one.
It's best for users that UI never displays true SoC(state of charge). They will not understand that the cameras and NFC payments don't work under true 10%, your degraded battery cannot safely reach nominal 100% voltage, etc.
Those are not pleasant facts that users need always be made aware of. 98% understood by BMS rounded up to 100%, actual 12% displayed as 1%, etc., should be tolerated.
