My remarks about older men being rare in Confederate service are based on census surveys, attempting to match every man of military age in a county to a service file. Younger men are fairy easy to find, but not the others. Another source of information for older men at home during the war are petitions to the governor on one subject or another. Militia registers are another good source for men at home.
There are always exceptions to the rule, like a frost during late April. Based on my experience, a man in his mid to late forties living in Tennessee is not likely to have enlisted in Confederate service. Based on your experience, there may be evidence to show that older men like Winfrey Scott in Tennessee often enrolled in Federal service. I have done no survey work with Federal commands.