I have done two drain and fills so far on my 4 speed auto V, and both times it took exactly 4 quarts.
Before I did the drain and fill, I checked the fluid (warm and running on level ground after going through the gears) to verify the tranny had the correct amount of fluid to begin with.
I bought five quarts of the Nissan tranny fluid the first time not knowing exactly how much I would need.
On the new unopened quart bottles , I marked with a sharpie the level of the fluid, so I would know how much an exact quart is when refilling the empty bottles with old fluid to verify how much drained out.
By carefully capturing all of the drained fluid and transferring to the empty bottles, I knew exactly how much fluid to add back. A check of the dipstick after driving the car after the procedure verified the correct amount of fluid. I have found the fluid level very easy to see on the dipstick.