According to the owners manual, the "normal service" interval for the trans fluid is 120k so you're good there as long as you haven't done too much heavy towing.
Amsoil MVATF is no doubt a great product. However I don't personally feel its a good fluid for these transmissions because they are so finicky about the type of fluid they have. Amsoil MVATF is a "one size fits all" kind of ATF and I prefer an ATF that is tailored for the ATF+4 specs. Castrol Transmax, Mobil, Pennzoil, and slew of others make a great ATF+4 thats Chrysler licensed. Keep in mind to be ATF+4, it has to be synthetic as per Chrysler specs. Here's a full list:
Licensed Brands | Chrysler ATF+4® Licensing Program
Although not officially licensed by Chrysler, Redline C+ is probably about the best ATF+4 compliant fluid you can get.
Also, I would avoid a flush. Heard way too many stories of it ruining transmissions. Just do a pan drop and install a drain plug so you can do do easy fluid changes in the future. Or spend the money for a PML or MagHytec pan with a built in drain plug.