Looks like they came and went. Dr. Holloway being the Asst. Surgeon from Jan. 13, 1864 (when he arrived at Dalton, GA from VA) to Oct. 5, 1864 at Jonesboro, GA when the AOT started its march that would take them to Nashville, would have served one of the longest times. When the AOT went to Nashville, he was transferred back to the Army of Northern VA and assigned to the 38th GA Inf. where he served until his parole in May of 1865. I wounder why Dr. Holloway in not listed in the source you found the other in.