This is coming!
I found same issue, so have provided new code for this today to NMedia. It will be in next version, to be released very soon (we are testing right now), you will be able to drag/drop meta groups within the list into the order you wish (in the PPOM sidebar of Product page).
If you go to the Product page, in the sidebar you just drag ‘n’ drop with the mouse. So put mouse over the description (not the checkbox) and drag “Project Details+” down the list to where you want!
OK, I have just tested the “release version” PPOM PRO v15.6 and it DOES work.
Instead of CLICKING with the mouse (which WILL select the option) Press DOWN on mouse and DRAG to new position, then RELEASE mouse and it will drop into the selected place!