What is disclosed is a novel method for reducing errors in IOP registration of a digital document system. In one embodiment, a number of digital pages (10, for example) are received in the image path. For each of a process and lateral direction of a first side of each digital image, a total amount of IOP registration error to be corrected is determined. A portion of the total IOP registration error is estimated that is separable error. Each of the estimated separable errors are subtracted from the total IOP registration error to obtain an amount of non-separable error in each respective direction. The non-separable error values are averaged to obtain an error value for each direction per-side. The error values are compensated for in their respective directions per-side by adjustments to the device in an amount which is equal in magnitude and in an opposite direction to the error.