I'm confused by the abbreviations you use: step1. fact.Ampl
Please state the load history completely and plainly. Define what one cycle is. For example is the load 0 kN, 6 kN, -6 kN, 0 kN, which is a fully reversed cycle, or is it 0 kN, 6 kN, 0 kN which is not a reversing load.
When you say a unit load, is one unit 1 kN or 1 N?