They will often tell you the "initial fill", this is basically the amount you need to drain and refill the pan. The other larger figure is pretty close to the total capacity of the system, torque converter, pan, cooler, lines, valve body assembly etc.
Most people do 3-4 drain pan and refill if you're at home.
Don't forget to check the TFT for the final check. The level should be in the B zone on the dipstick. Simply search the internet for the 6R80 TFT check pdf. You can check the TFT on some models through the in-cluster MFD. Some people use a IR thermometer, those are sketchy because of the emissivity of the pan. These days I just use a K-Type thermocouple attached to a DMM. Because of where the dipstick is on the 6R80 and how shallow the pan is, you could probably also use a meat thermometer.