If a project has more that 8 Inserts on any tracks in N8.2 and it is loaded back into N7 for some reason, any Inserts in slots 9-16 will be lost (they will not be there) when the project is returned to N8.2 if the project was saved in N7.
I can understand this, but it is something to be aware of - might be safer to just stick to the original 8 slots that have been sufficient for all these years, at least until there is absolutely no reason to ever return to N7 (or any other previous version).
Actually, I see that a message appears when loading a project with more than 8 Inserts on any tracks into N7 stating that the excess inserts will be discarded. This is not entirely true, as they do not appear be discarded if the project is not actually saved in N7.