I didn't catch that one, TERRY308, but I would guess that Joshua permitted Ben to get away with it as a sign of his new respect for the beleaguered servant. Did he call Mr. Collins "Joshua" before or after he received his freedom? Moving to a first name basis might have been a sign of his new status.
It seems to me that Ben Stokes was the only person to make it through 1795 in any sort of positive state. After everything that he went through, he certainly deserved it.
ProfStokes