If a paper has 4 or 5 authors, it will list all 4 or 5 with these setting the first time it is cited. – the second time it is cited it will only list the first author et al. A 2 or 3 authored paper will always list both or all three authors with these settings. This is common in humanities, but in sciences, it is rare to ever include all authors at the first citing unles 3 or less.