While I agree the owners manual says that fluid changes aren't required in normal driving conditions, I don't think you can ever be too cautious when it comes to maintenance. After all, the manufacturer isn't going to pay to repair the transmission when it fails out of warranty.
That being said - it looks like 3.5 quarts is what you can expect from a drain and fill situation.
These transmissions are sensitive to fluid level. Here is a web page directing you how to make a dip stick to accurately measure the fluid level. Don't forget, you need a scan tool to test temperature of the oil.
It seems that every few months we hear of a new transmission coming to market. It’s hard to keep up with all the different transmissions and different ways of checking their fluid levels. One day soon, you may find yourself faced with a 948TE 9-speed transmission in your shop. The 948TE appears...
My 2 cents... I would only be concerned changing the ATF if over 125k and you plan on going another 100K. Over time water and condensation finds its way in there and can effect fluid level and performance. My Toyo Sequoia is a sealed trans, has 160k and from research, fluid change is needed too last 250k+ which these vehicles easily do. An ATF change can fix things like hanging in gears, harsh shifting..etc.