When clicking on an author name in a detailed record, EBSCOhost performs a phrase indexed search for the author name with the AR field code. Because it is phrase indexed, the search will only find that exact phrase and you are likely to get fewer hits.
When searching for an author with the AU field code, EBSCOhost will search for the name whether it is entered first name, last name OR last name, first name.
Clicking on the name MACKENZIE, SCOTT A. from detailed record will only search for "Mackenzie, Scott A."
Searching for the author with the field code: AU "MACKENZIE, SCOTT A." will search for MacKenzie, Scott A. or Scott A. MacKenzie.