Dot-matrix holograms created by two-beam writers usually contain grating-dot position errors. The position errors may result from lens aberrations, rotation mechanisms, or beam direction inaccuracy, so they are not controllable. When the components of a two-beam writer are not reinstalled, the position errors of the grating dots created by the writer can be reproduced. Hence, position-error curves derived from the regression of the data points on position-error diagrams have some high-end applications. Two applications of position-error curves of dot-matrix holograms are proposed. The first application is to determine whether a dot-matrix hologram was created by a specified two-beam writer or not. The second application is to determine if two dot-matrix holograms were created by the same two-beam writer with the same component installation.