why do you need to be honed with deck plates

Supposedly, one can actually measure the distortion. I would think it would be local, like around the bolts, but that's what I read. The head, gasket, and bolts that are being used in the build are torqued to spec. Then the cylinders are measured and recorded. The torque plates are then installed, but not tightened to spec, but to recreate the distortion.