It's just a fancy way of saying the all-but-one applies . While the end-of-run is the basic spot, IF the foul occurred behind the basic spot but beyond the LOS, the enforcement spot is the spot of the foul.
Note, if the run ended BEYOND the LOS, but A's foul occurred Behind the LOS, the previous spot would be the enforcement spot (10-4-2e).
Hope this helps.