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As as with any fluid change you want the recommended amount which in this case is to the "fill plug hole" level. You should never be concerned with how much came out because how do you know the last idiot didn't put too little or too much or that some fluid has been lost over the years or level has increased due to moisture? Always put the recommended amount no matter what comes out... That goes for any fluid.
After following the thread I wanted to add my 2 cents. I had the same problem as others, more fluid came out that what went back in. What I learned from changing the transfer case fluid is rotate the wheels. I was able to get another 200ml in both front and rear diff and match the listed capacities. I guess it draws oil into the nooks and crannies and lets out the air bubbles. When I changed the transfer case and rear diff fluid I had the GTS on front ramps and rear jacks, so with the car in Neutral I just rotated the rear wheels. For the front diff I backed it off the ramp with the suspension at terrain lift and topped off the front diff till it spilled per the procedure. Its been running smooth and quite ever since.