I'm a supervisor in a large lab. About 11 months ago we had to let our long time, lead digital designer go and I had to take over as designer until VERY recently. Basically self-taught on 3Shape over a 4 year period (and certified in Sirona InLab design as well). Not to brag, but I'm a fairly decent designer. I average about 30 full contour crowns a day and maybe get 2 a week back that needed redesigned or had a flaw in them. When I took over that position our remakes plummeted and the feedback from our clients was astronomical. My record for one day of design was 46 crowns. I was NOT on unit pay (again, I'm the supervisor) and I can tell you that forcing your designers to do more than 30 a day WILL result in quick burn out and inferior product. Plus more difficulty and harder work for the ceramists which in turn gets THEM frustrated. 5 mintues per unit is ideal, but since when do we get ideal cases? Things like malocclusion, tight contacts, proper thickness needed for the material, path of insertion (and lets not forget mis-scans!) all contribute to slower design times if you want a quality product.