There is no such thing as Dexron VI "low viscosity", so if they are sticking to the properties of Dexron VI licensed fluid then it is the same viscosity as regular Dexron VI. One might assume what they mean is that the initial viscosity of a Dexron VI fluid is somewhat lower than the old Dexron III fluids, but the reason for that is because the Dexron VI fluid is more shear stable than the old Dexron III. As a result once in use the eventual viscosity is either the same or higher.
If your vehicle specifies a Dexron III or VI fluid then yes it will be fine since Dexron VI supersedes Dexron III licensing. What does the owner's manual say for the fluid specification or license?