I performed duties at or above the GS11 level as a liaison officer for two years even though I was an active duty SFC E7. That assignment was authorized civilian clothing allowance so my ROK counterparts assumed I was the same rank as my predecessor, a GS13 who started as a GS11, as evident by this Certificate of Appreciation from the CG, ROK Army Intelligence School, MG Kwon, identifying me as a GS11. This is further supported by a Letter of Appreciation from the incoming 501st MI Bde Commander, COL Marvin, thanking me as a civilian liaison officer for translating with DVs and coordinating a high profile ceremony with related office calls and social events; of course he soon realized I was active duty but he kept faith in my ability to perform at the GS11-GS13 level and gave me even greater responsibilities.