I worked for a bit as a high end roofer (USA), this is the first I'm hearing about different classes of measuring tape. We always used Stanley fatmax tapes, and so did just about every carpenter we worked with. I wonder how accurate that tape is?
I assume it was pretty accurate because we would always fuck with the new guys when they drew a cut line and asked what side of the line your supposed to cut from.
Ha! Gonna let my old boss know. We also did sheet metal fabrication, but very rarely did things need to be accurate to a 1/32nd