Well according to the attached documentation from ZF, maker of the transmission, the severe service schedule including frequent high speed driving, sporty agressive driving, and/or towing says fluid change every 80-120,000 km or 8 years. So in good ole american miles, 50-75k miles with only the proper fluid listed.
Everyone may not fall into that category, but I think it a good idea to be preventative and follow the earliest manufacturer recommended change at 50k miles.
Also interesting to note the recommended fluid is not fully synthetic, but a blend.
