Like most answerers said here, Tang Soo Do is not Karate and you must totally aware about this, because if you are practicing one style, then you must review its history and you need to search more about some important details as part of additional knowledge.
Reference: http://en.wikipedia.org/wiki/Tang_Soo_Do
Besides, double promotion is rarely happen, there are some gifted people and if the instructor seen it that he is totally deserving then he will grant such opportunity to his practitioner.
True is, I don’t want to insult you, but you for not knowing the differences between Tang Soo Do and Karate, I am sure that you didn't deserve to get a double promotion, maybe you fall into a mcdojo and such is the reasons why such thing occur in such training place.
...........................................