Following their requirements, no matter what.

Competition is not about right or wrong, good or bad.  Judges are always right.

The link I gave you is for the so-called urtext edition (German for original text edition), which is for more matured users or strong teachers, or both.  For you right now, it is 牛刀杀鸡。 Sorry that I even mentioned it.

It sounds that your son is very talented.  Congradulations, win or not.  This is the real thing.