I've never got into the technical what, where, when and who, as I hate reading and living in downtown Churchill (20 cavemen, 1 scared cave lady, 2 dinos, 3 kangaroos, 1 coala, 1 wombat that eats roots and leaves, and 1 henpecked duck) I don't get a chance to talk laser with too many in the know 'cept some jerk in the mirror.
All I know is that mine cuts acrylic/engraves like butter with a crystal clear edge, the holes in the base was to poke out wrong pieces with a toothpick (it's 55mm x 75mm)... and I haven't mastered the wicking technique... see thru top... (75mm x 75mm x 50mm) , buggered this up by trying to import a "wise man" (cest moi)... the laser objected... but the jigsaw was perfect... (160mm dia.).
So mine must be a CO2... does that mean I'm an environmentalist or a filthy polluter?
If your first cut is too short... Take the second cut from the longer end... LBD