An application of this is demonstrated in the demo circuit MiddleBrook.qsch. It plots the loop gain by convoluting the voltage and current gains into one loop gain(assuming feedback goes only from the designated output to the designated input).
If you uncomment the the step command, it allows you to plot the phase margin versus the output voltage. It is common for an audio amps’ phase margin to vary wildly as the output moves off center and approaches a rail:
–Mike