Just for the record the vertical movement of tectonic plates is most certainly taken into account. The science even has its own name, Isostasy. Isostatic sea level changes have been observed for millennia, particularly in locations still rebounding after the last ice age.
Stockholm for example has needed to rebuild waterfront infrastructure many times as the ground on which it is build slowly rises. (Don't have a link sorry. I caught a train through Germany, a bus from Denmark and then a ferry.)
