I used the mod once and immediately uninstalled it again. When I upgraded a belt it marked all tiles for deconstruction. So the belt was not moving any more and the robots where picking up all the items from the belt. Only after this they placed down the new belt.
I expected it to work like the vanilla upgrade planner where it marks the belt for a replacement with the next tier. Like this the belt still continues working and the bots only replace the belt without picking up the items

Yeah, the old version was pretty bad! Finally got around to updating it, works like you would expect now, give it a try!