Jerry,
Glad to hear you've "got the fire" ! As far as men and units moving around alot ; you especially see that in the early days of the war and in the last year or so of the war. In the early days of the war, some Texas units were moving off to Virginia ( what was to become the famous Hood's Texas Brigade) , some went off to the Tennessee/Kentucky area to fight with A.S. Johnson , some moved up toward Indian Territory to "throw in" with Stand Watie's Confederate Cherokees / Creeks/ Choctaws /et al and some of the units stayed in the Texas area. After some of the very first battles there was a lot of movement of individuals ( usually officers) , but sometimes companies and even entire battalions ) back to other areas to join other regiments . Whether it was tactics, logistics, politics or egos or all four , you did see a good deal of movement in the early going as men were kind of getting a "lay of the land". Now , I don't mean you had huge groups of troops saying, "gee, I think I want to go fight with Lee, so we'll just hop off to Virginia for a while" . But especially in Texas , you did have some merging of mounted battalions with independent companies , forming mounted regiments and so on. Also, some of the early unit names and nicknames went by the wayside as more formal unit organizations and command structures began to "gel".
It is possible that "your man" could have started out with the Orleans Light Cavalry and at some point in the early going , his company could have fallen in with the 11th Texas Cav , as they were fighting in the same general area ( at that that time ) . Now that assumes that the A . Weathersby in the 11th Texas Cav roster is your GGGrandfather. So that is speculation on my part.

Now, on to the last days of the war. By the last year of the war , the ravages of combat deaths , disease , destruction of crops and forage for horses , had taken its toll , especially on mounted outfits. Alot of previously mounted units found themselves unmounted ( much to their chagrin) and consolidated with other dismounted units into infantry units. Granbury's famous Texas Brigade of the CSA "western army " ( Army of Tennessee), had several regiments that were made up of dismounted Texans .

My point is this , it is possible that your GGGrandfather fought in 3 or 4 different units during the war. The other thing is that if was ever wounded and was sent home to recuperate (I don't take time for spellcheck) he might not have been able to join his old unit when he returned to active service. That happened to my GGGrandfather at the Wilderness. He was shot up pretty good (bad) and was sent
home to Alabama to recover . When he had healed up , two significant things had happened , one was that my GGrandmother had been conceived and two, he could not get back to the Lee's Army because Sherman was between Alabama and Virginia . So he "threw in" with some local militia and spent the balance of the war in Alabama, growing corn and making babies . Sorry if that offends you ,
but that's what he did.

Sorry for the long story but it might help explain how things could happen like serving in 3-4 units. I just thought of one more possibility , if he was ever captured and paroled and or exchanged , there is a real possibility that that he would signed on with another unit following his release. You just aren't going to know these things until you get hold of his complied service record which is on Film # M227, Roll 38. It looks like at least 3 of his enlistments are on that Roll ; I did not look for his "Orleans Light Cav." experience. So, get those service records and that should give you a fairly good idea who he served with and when he served with them and if he was ever wounded or captued/paroled /etc.

Did you know he was a 1st Lt. in Co H of Baylor's Regiment , Texas Cavalry,2nd Regiment Arizona Brigade?

By the by, each one of these three units we've been talking about saw combat , and from what I can see from the regimental records , they probabnly saw a good bit of it.

By in large , Texas troops were always in high demand by commanding officers of frontline commands. Senior officers from Marse Robert Lee himself on down to the regimental level were well aware of the tenacity and ferocity with which most Texas units fought. So , my guess is that your GGGrandpa ( no disrespect intended) didn't spend too much time "in the rear with the gear" , as we said in 1969 ( from my personal experiences ) . There is a very good reason why those Texas units were absolutely decimated at the end of the war.
Have a good weekend. Get those records of your GGGRandfather's military service and then you can really narrow your search as to who did what, when and where. Other wise, you could spend too much time ( it would be for me) chasing down units and campaigns that your ancestor may not have had anything to do with. Now if you just have an interest , go ahead; however, if you are tracking down "your folks" like many of the rest of us do , you might want to narrow your search