Here is another example of war time POW oath taking in the western theatre.
I just examined a record of a Georgia Confederate soldier who was listed among "Deserters from the Rebel Army who have taken the Amnesty Oath at Chattanooga, Tennessee" on 21 OCT 1864. He was received at the Louisville Military Prison from the Department of the Cumberland at Chattanooga on 24 OCT 1864 and released north of the Ohio River on 26 OCT 1864 to remain there until the war was ended. There are two oath taking records in this file: (1) the Amnesty Oath (aka an Oath of Allegiance) at Chattanooga on 21 OCT 1864 and (2) the Oath of Allegiance taken on 24 OCT 1864 at Louisville.
I think in both records that they are referring to the Lincoln Amnesty Oath being taken. It could have been administered twice just to insure that the released POW understood what was required of him. The date order of these documents shows movement to a place across the Ohio River beyond the reach of the Confederate army, not the other way around.
The flow that George described (10 MAY 1864 at Louisville, and 23 MAY 1864 at Chattanooga) represents a flow in the opposite direction. This strikes me as odd since the Confederate army was still in northern Georgia and the Atlanta Campaign was in its early stages. It doesn’t seem logical that the Federals would release an oath taker in reach of the Confederate army. Returning home, his Federal oath would have been considered non-binding to the Confederates. He could have been easily returned to the ranks where every soldier was needed.
My research has indicated that from December 8, 1863 when the Lincoln Reconstruction Plan was unveiled and an Amnesty Oath prescribed until the Johnson Amnesty Program was announced at the end of May 1865, POWs released into northern society took the Lincoln Amnesty Oath and were paroled (their personal promise) to remain north of the Ohio River or otherwise outside of the seceded states until the war was over.