Is that to suggest that the bed was perfectly flat + level before heat was applied? Most printers I've worked with have either fiberglass (in the form of FR4 P

Is that to suggest that the bed was perfectly flat + level before heat was applied? Most printers I've worked with have either fiberglass (in the form of FR4 PCB material) or steel beds, usually with some additional surface on top (glass, PEI, etc) and none which I've even seen have been precision ground. Unless you're going to utilize a precision ground print surface (and have the print head and motion stage trammed close to perfectly square), you're still going to wind up using mesh level compensation. I guess I don't understand how a material with a low coefficient of thermal expansion changes the math any.