The answer is not that simple. The output to DISBOUT is with respect to the beam coordinate system defined by SCOOR. The “Rel. Axial Disp” is the change in length projected to the local coordinate system defined by the field SCOOR on *SECTION_BEAM. For example, when SCOOR=0 the element coordinate system updates with respect to the average rotations between the two nodes. If the rotations at nodes n1 and n2 of the discrete beam element are fixed, the SCOOR=0 local coordinate system would always coincide with the initial local coordinate system of the beam, which means that the r-axis would remain along the initial (at t=0) n1-to-n2 direction, regardless of the translation of the two nodes. However, in a case with SCOOR=12, the system updates so that the r-axis lies at all times along the current n1-to-n2 direction. In general, the “Rel. Axial Disp” result will be different in these two cases.