Don't have a sample work book (hint, hint) but it looks like the arguments might be out of order, in addition to the other comments
SUMIFS(sum_range, criteria_range1, criteria1, [criteria_range2, criteria2], …)Pauleng_hours = Application.WorksheetFunction.SumIfs(mtd_ttl_hours, maj_group, "ENG", bill_summary, "LABOR")