Not sure how applicable today's military terms are to WBTS designations. However, between the early 1950s and my retirement in 1980 most of my service was in "detachments" (Air Weather Service, AWS).The "host base" provided barracks, feeding, hospital, etc. Our chain-of-command ran from the Detachment (at an Air Force or Army Aviation base) to a parent Squadron (normally a 'detachment' at a "numbered" Air Force, i.e., 8th Air Force, 2nd Air Force, etc.) to a Wing (normally 'detached' at a Major Air Command---Strategic Air Command, Tactical Air Command, US Air Force, Europe, etc.) HQ, AWS was a "Service" unit..(as were our "sister" services...Airways and Air Commnications Service, Air Rescue Service, etc., under the Military Air Transport Service (MATS--later to become Military Airlift Command, MAC).

We were "detached," (to our host base), "for records, rations and quarters" and provided our services to our host base--but our personnel matters (reassignments, promotions, training, etc.)were through our parent Squadron/Wing/HQ, AWS.

We could be "detached' from our "Detachment" for temporary duty ('TDY') and sent to another base to fill-in for manpower shortfalls at that base's weather station or to provide additional "warm bodies" for stepped up operations at some forward location.

Your ancestor was obviously a "specialist" with unique skills not normally called for as a "grunt" within his infantry company/regiment and was apparently "detached," or "detailed,"..the latter probably CSA for "TDY" where his skill was needed most. My guess would be that "detached" was a more or less permanant move,(today's PCS [Permanent Chage of Station]} while "detailed" would comparable to today's TDY.

I suspect most veterans reading this well remember the old "...needs of the service come first..." which occasionally put one working outside one's "MOS" or "AFSC"...digging bunkers or filling sandbags in 'Nam as one example.