Thank you. Once again, great information. I have been already adjusting for duplicate vertices without realising it was being caused the plugin. I was thinking it was just a normal thing. I came across doing it when I would go to apply a face and it wouldn't take, I found that if I used merge at the vertices points first that then it would work. This explains alot. Also why models that were fine on one export would claim to have over 65,000 vertices on the next. I had been getting around it by cutting the models into pieces. I can see going back and re-exporting my models after using the merge function in my near future.
One caviat I would add for the Mesh-→Merge-→By Distance. Is make sure to go into the pop up that will appear to be sure thedistance tis 0.0001 at maximum if not lower or else you might find some parts of the mesh you didn't want merged ending up merged.
So much great information I am now going to have to shoe horn into my brain.
@Stone Blue