The actual quote usually is that "you do not need to change the fluid during the life of the transmission." The issue is that how long do you want that life to be?

There's a bit of a religious argument going on about this right now so don't be surprised at an uproar.

MB Germany has reversed this position. They now say that the fluid must be changed before 60k kilometers (40k miles) but it is not necessary thereafter. MB USA has been silent on this change. My hypothesis is that they are afraid of being liable for all the failed transmissions to date as the transmissions do at least last through the warranty period.

I would get it changed. Other than the tinfoil hat crowd claim's (OMG You Are Doing Something That MB Doesn't Tell You To Do!!) it isn't hurting anything. My experience as well as others' is that there is a noticeable improvement in shift smoothness afterwards.

Note that if the transmission is already damaged changing the fluid won't cure anything but it can lower the future rate of deterioration.

Note also that for most models (I think your year is included) getting all of the fluid is a bit time consuming. Don't be surprised at having to pay for over 1 hour of labor. It is a little more involved then just pulling the drain plug. Take it to an indy who knows what they are doing.