Question about the different zoom commands/engineering scale within DraftSight

OBO David Anderson:

I have an issue to report or a question about the different zoom commands within DraftSight. If I were to set up a site plan with an engineering scale such as at 1”=60’-0”, 720xp, or at 1”=100-0” ,1/1200xp, (because I do know the scale factors from learning Autocad), then why does Draftsight operate differently when applying the same concepts to zoom inside a viewport to that certain scale desired.