Tool/software: WEBENCH® Design Tools
Testing DC/DC converters that have the DCS mode, and some other devices, they enter either a 'pulse skipping' or 'semi-standby' mode when the load is very low... this requires that the steady-state simulation runs for something like 50 ms to capture a full cycle of the behaviour, and, similarly for a load transient, if the load goes to a low-enough value that the DCS mode is entered, the simulation needs to run long enough to show the behaviour in the DCS power-save states.
Maybe I'm a bit slow, but I could not see a way to set up the steady-state simulation for that long a period??