They show him still in Co. B, 27th Batt'n, VA Mounted Rifles as of 12/23/63 and indicates he was promoted to 4th Corporal since 30 Oct. 1863. As of 4/30/64 shows him still in the 27th. Then as of 8/31/64 went into the 25th VA Calvalry. The muster roll for 10/31/64 shows him on horse detail since 9/17/64 which matches up with your info. The next muster roll dated 12/31/64 shows him AWOL since 10/17/64 which also matches. The last roll shows that he appears on a Roll of Prisoners of War and was paroled at Cumberland Gap, KY on 4/29/65 by Col. Wm. Dillard, 34th KY Infty Vols.
As I mentioned in another post I have his original Oath of Allegiance to the Union, dated 4/29/65, and he writes in the oath that he was "exchanged" at Cumberland Gap, TN and the oath is attested/signed by Union Col. Wm. Y. Dillard and another Union Lt. whose name I can't make out. After that he went home to Lee Cty.
I have a picture of him at his 45th reunion (in Amarillo, TX) and I have his CVA reunion pin, in 1910, with other members of his unit. As I remember about 10 of them.
Again, thanks very much for going to the trouble for me,
Ken