I asked, will update.
I thought the blog post was extremely informative. Seems like Mercedes was making multiple developments when upgrading from 7g to 7g+.
Didn't realize the OEM filter was so advanced and better than aftermarket filters.
If you got an early model 7g+, and didn't get the upgraded filter and deeper pan, IMO it's worth the money to upgrade to deeper pan with the advanced filtron filter.
The 7g+ is very close to the 9g. In fact I believe 7g+ has the hardware to do 9 speeds. The similarity of the transmissions may be why the 9 speed fluid could work in 7g+.