Automated multivariable control can reliably control the operating point closer to constraint limits and optimization targets, because, as the operating point and constraint limits move due to normal process variation and disturbances, automatic response can be relied upon to keep the operating point from exceeding alarm and constraint limits. With manual multivariable control, the operating point tends to be kept farther away from limits and targets, since manual response tends to be less reliable, but this usually translates into missed optimization potential.