My working theory is that Andrew's wife, Catherine, may have been a Campbell. There are three facts, which taken together suggest this as a possibility: first, that Andrew served as a substitute for Robert Campbell in connection with his second term of service in the Revolutionary War; second, that Andrew moved to Rockbridge County, Virginia, where Campbells from Berkeley County, (West) Virginia also moved; and third, that son David's first son was named Campbell Bowers. Those facts are suggestive that Catherine was a Campbell, and that Andrew's service on behalf of Robert Campbell may have been motivated, at least in part, by family considerations.
Catherine married Andrew BOWER (Sr.), son of Henry BOWERS (Sr.) and Catharine. (Andrew BOWER (Sr.) was born on 16 Feb 1753 in York County, Pennsylvania 3 and died on 3 Nov 1833 in Montgomery County, Indiana 4.)
1 Deed Books D-E, 1798-1806, Rockbridge County, Virginia, FHL Film No. 33,763.
2 1880 Census, Marion County, Missouri, Roll T9_702, E. D. 21, Page 411A (Ancestry.com Image 17 of 29). See entry for Jacob Bower.
3 War of the Revolution Pension File No. S16324 for Andrew Bower, National Archives.
Indiana Daughters of the American Revolution, compiled and edited by Mrs. Roscoe C. O'Byrne and others, Roster of Soldiers and Patriots of the American Revolution Buried in Indiana (Originally published 1938, Reprinted by Genealogical Publishing Company, Baltimore, 1968, Crawfordsville, Indiana District Public Libary Call No. RL 973.3o), Volume 1, Page 66.