Congress revised the law several times to extend age limits, first from 35 to 40, and later from 40 to 45. The law of Feb. 17, 1864, called seventeen-year olds into the junior reserves, and men between the ages of 45 and 50 into the senior reserves. Many of the older and younger men had already been enrolled as substitutes -- someone not liable for military service who could be certified as able-bodied and of sound mind. When Congress abolished the law allowing substitutes, it made both the substitute and whoever engaged him to act as his substitute liable for service. It doesn't sound fair, but that was the law.
Most of us tend to forget about the needs of families at home. Loss of younger, able-bodied men to the army severely crippled the ability of most families to manage a farm, handle livestock or defend themselves. For these reasons any man not required to serve was badly needed to care for women and children. Older men were more likely than younger teens to recognize the need, but in any case, most of them stayed put on the farm.
From a military standpoint, Confederate officers usually found it impractical to enroll older men and younger boys. Older men were much more likely to suffer from various illnesses and be absent from duty for one reason or another. Furloughs and discharges tended to generate forms to fill out and send to the authorities, and unpleasant questions from senior officers as to why so men men were absent from duty. Younger boys under age eighteen tended to create other concerns. If parents wrote asking for their return, more forms had to be completed and more letters written.
Bottom line, I would be reluctant to match the names of men outside the standard age range to Confederate military records without support from the records themselves.