By giving this mummy a designation of WV 22 implies that the mummy came from that tomb. Certainly, we know the mummy was not removed from WV 22 in modern times. The mummy may well be Amenhotep III but to put the designation WV 22 on that mummy is an assumption based on insufficient evidence to my knowledge.
True the badly damaged mummy was inscribed as Amenhotep III but lying in a coffin trough for Ramses III with a lid for Seti II. It is also true that Amenhotep III and his queen Tiye enjoyed a long reign and as a result, the kings tomb in the valley, WV 22, was more than likely finished and well provisioned with their funerary equipment, that is not proof the king or his queen or the mummy in question were ever buried in it.