the problem of unused vertices is because there are some wrong calculation in the list of vertice, i think the script load ALL VERTEX from list, but a singular object don't have all vertices... the game use this method to compress the vertices list, because the similar vertex are not written, is a kind of compression.
I make some test to understand the compression, you can compress only 10% or 20% of world file and if you utilize no similar vertices (example in the damaged-undamaged objects ) there aren't compression... But Knight Errant are simply save/load all vertices otherwise the script becomes much slower.