Thanks for your help so far. I added some questions about another order my father received. Could you look again at my discussions? Thanks.
Afraid I can't help much, "HQ cs" could be Headquarters Clearing Station, or Chief of Staff but it is not capitalized which I would assume it would be for either of my two suggestions which would seem to indicate an abbreviation of a common word, not a title.
SOS for Service of Supply was replaced by the Military with Armed Forces Service in 1943, but SOS continued to be used for theater specific units, ie... European Theater, Pacific Theater. The 6T might relate to a designation within the China theater but I am afraid I don't have much information on the CBI as we only had one small unit, the 124th Cavalry Regiment which served there.