Jim, John Howerton was a first cousin of my gggrandfather John Thomas Howerton.
George Cooper wasn't included on the February 1863, payroll, since he had deserted from the 27th Arkansas on December 20, 1862, and was dropped from the rolls. I don't know why John Cooper wasn't included on the payroll, unless perhaps he was on furlough at the time. The way I read the document, it lists the men actually present and paid on that date; at least that's what the paymaster's endorsement (signed by W. E. Gibbs) seems to say. Since John Cooper was among those men who stayed in the fight at Prairie Grove, but doesn't appear on the payroll, I can only assume that he was on an authorized absence on that date.
And that may explain why another 25 or so men do not appear on the roll. I know that some of the men were wounded, and never showed up for duty in the 27th Arkansas, so they must have died or were discharged or furloughed because of their wounds.