Hello! I have been laser cutting with Pololu for a few years, and I just found that you offer now cast and extruded clear acrylic. I have the impression you only offered one before, and I would like to know (if this is correct) which one it was. I need it for scientific research so I need the cuts to be accurate and the thickness to be reliable. I read that one of the acrylics has a less reliable thickness, does that mean that the surface is not really flat? Thank you very much!