Quote from Kueken531: Go
A 1 x 1 square can easily support a path with a bigger distance of 1, though, given the appropriate mazing. Even just crossing the square diagonally will be a greater distance than 1. So it should indeed be possible to create a valid path with pathing costs > 65536.
Well i wasn't sure, But anyway i think it highly unlikely he goes beyond that. You need to take into account pathing blocks themselves and minimal distance step, not to mention other stuff on map.