Here's my two cents worth:

James gives his unit as Co. A, 2nd Texas Willis Battalion Wall’s Legion. Asked the question were you transferred from one command to another, he answers - Not transferred. I take it then that he served in one unit only, for about two years

…..

Here are the muster rolls for the Company, Note the number of holes. It’s quite possible your man served during the period March 1863 and dropped from the rolls by September 1864.

Muster rolls for Company A, Cavalry Battalion, Waul’s Texas Legion, also known as Capt. J[?] Thomas Co. Waul’s Legion Texas Vols.

Organization to June 30, 1862, Stationed as Camp Wauls
First Muster to Aug. 31,1862, Station not stated
Sept. & Oct., 1862, Stationed at Cold Water
Jany & Feby, 1863, Stationed at Camp near Vicksburg, AKA
Capt. J. C. Rowland’s Company, Cavalry Battn, Waul’s Texas
Legion
Sept. & Oct., 1864, Stationed In the field
to May 1, 1864, dated May 14, 1864, Stationed In the Field
No further rolls [Starts at Card #66]

M323: Compiled Service Records of Confederate Soldiers Who Served in Organizations from the State of Texas