For some practical disturbances and uncertainties, acceptable control systems can be designed even for MIMO ill-conditioned processes. A class of ill-conditioned processes has been studied where an inversion-based control system is not sensitive to the diagonal input uncertainties. We show for this class that element uncertainties arising from usual element-by-element model identification do not significantly degrade the control performance. Some useful measures for uncertainty effects on the control performance, stability, and inversion are proposed.