@jleach, great idea with the #2 SQL. I found my quick solution below:
SELECT tblTemplRateAudit.PN_Ext,IIF( tblTemp_Rates_A.PN_Rate is null,Dlookup("[PN_Rate]","[tblTemp_Rates_A]","[PN_AC_Category]='"&"Blank"&"'"), tblTemp_Rates_A.PN_Rate) AS Rate, IIf(tblTemp_Rates_A.PN_AC_Category is...