Oh yeah sorry guys, forgot to update this...
Yes, funny enough a few hours after posting this (4am) G.INP was activated on Upstream and it has done exactly what I'd hoped it would.
The line is a lot more stable now as you can see, no more errored seconds unlike the the days following... I'm not sure but I would say that even the downstream (which already had G.INP) seems to have improved a bit more with the additions of the error correction on the downstream.