A loose formation of untrained rabble archers should not be able to unflinchingly stand with 100% accuracy against a heavy cavalry charge, eat the charge, and then continue to shoot at all the mounted troops as those troops have to stand around and slowly cut each archer down.
I'm no professional expert historian, but I'm pretty sure there is at least *something* wrong here. It's either archer morale, archer accuracy, archer damage, archer speed, unit movement speed, or lack of unit collision and charge damage, or some combination thereof. I can't speak to the efficacy of one short bow vs another against every type of armor imaginable, but I can tell you from a human stand point that almost no one can keep their formation as a light rabble of forest bandit archers against a charge of medium to heavy cavalry.