In this case, the contractor was removing thinset on some jobs and several coats of epoxy with quartz on others. The important detail is that tungsten wear bars were not aggressive enough for the work.
For this kind of removal, Lavina clockwise PCD is usually the cleaner first step. PCD bites into thinset, glue, mastic, and quartz-broadcast epoxy more aggressively than scraper-style wear bars. Direction still matters: the tool direction should match the grinder rotation so the machine tracks more smoothly and the operator keeps better control.
Use this setup when the job needs stronger removal, not when the goal is fine grinding or polishing. After the coating is removed, the floor should normally move into metal bond grinding to clean the scratch pattern and prepare the surface for the next stage.