Yes I know exactly how much time I saved you. I went thru the same problems when I was learning how to use the program.
A major complaint of mine is how Plasmacam uses the offset feature when drawing in Plasmacam (not the same as when you convert to cut path). In Autocad when you offset a line, the line you offset doesn't disappear like it does in Plasmacam. When you have a closed item in Autocad, and offset the line it does make the line shorter. (That same triangle you drew in Plasmacam would be a smaller triangle in Autocad without the crosses at the end.)
Plasmacam should ask if you want the original line deleted. I use the offset feature when drawing a part all the time. I do very little drawing in Plasmacam, I use Autocad 99.9% of the time and import a DXF file.