The long fist way to execute a Beng Quan always start with a downward parry followed with a vertical punch. So, a downward parry can deflect an incoming chest level Beng Quan.If you say, "Beng (Wood) can conquer Beng (Wood) and you have options," then how useful is the Xing Yi 5 element theory?
Besides the 5 elements, there is also the "symmetry".
In MA, a principle/strategy/technique can sometime counter itself. It's like to play the Go game. If you always put your chess at the symmetry position, you will never lose.
For example, when both A and B throw Beng Quan at opponent's chest, who will win? If they both punch at the same point, their fists should meet.