A difficulty of freeform surfaces evaluations lies in a setup of a coordinate measuring system in general, when it is not possible to use the standard system of alignment by a point, a line, and a surface. An algorithm for the measurement adjustment using a small workpiece coordinate system movement and rotation to achieve a smaller least square error of the produced surface for a given freeform surface defined by the function of two variables is considered. The algorithm is using the Newton method for calculation of the orthogonal distance of a measured point to the given surface and also for minimization of sum of the distance squares. Numerical results for an example are given.