battery never above 5V or below 3V, is AREF(EXTERNAL) needed?

Hi guys,
I have a cool project with an analog sensor I'm working on that is powered by a 3.7V Lipo. The battery has circuit protection so that the voltage never falls below 3 volts. I understand there are situations where changing the AREF is neccesary, but will the INTERNAL2.56V analog reference decrease if the microcontroller(attiny85) is powered by 3V?

I know this question is a bit noobish but I'm having trouble finding a definitive answer, and since there is no serial port on the attiny85, testing this would be a bit of a pain.

Page 134 of the datasheet:

Note: 1. The device requries a supply voltage of 3V in order to generate 2.56V reference voltage.