Sifakis' Compendium of the Confederate Armies is a very reliable reference book, but some of the primary sources he used in his compilation have the occasional error.
There is no record of Erastus L. Black being promoted to lieutenant-colonel. During the reorganization at Saltillo, Mississippi, on September 10, 1862, the 12th, 14th and 23rd Arkansas Regiments were field-consolidated, and a new slate of officers was elected --
Oliver P. Lyles, colonel.
Abraham A. Pennington, lieutenant-colonel.
Erastus L. Black, major.
These officers held their positions until the end of the war. Colonel Lyles and Major Black were captured at Port Hudson, but were exchanged and returned to duty by April 1864. Lieutenant-Colonel Pennington was absent on detached duty when Port Hudson surrendered, and so missed being taken prisoner. He never returned to duty with the regiment, but retained the position of lieutenant-colonel.
Under the old regimental system in use at the time of the Civil War, a volunteer officer was commissioned with a specific rank within his regiment. He could be temporarily detailed to another unit, but he retained his rank and position in his home regiment. As long as Lieutenant-Colonel Pennington retained his commission, Major Black could not be promoted to the rank of lieutenant-colonel of the 23rd Arkansas Regiment, even though Pennington has absent from the regiment on detached duty for most of the war.
The parole lists were compiled from parole forms, which listed the parolee's name, rank, company, regiment, date and place of enlistment, age and place of birth, and a physical description. The form was normally signed by the parolee, witnessed by a U.S. officer, and endorsed by the Confederate and Union commanders (almost always signed in their behalf by subordinate officers). Therefore, the rank reported on the parole list is correct.
I don't know why one of his CSR cards lists him as a lieutenant-colonel, other than a clerical error. If the card in question is a POW record, then a clerical is certainly the problem. Lots of the POW records contain bad information.