Thanks, but how do I sum across a row of the table given that the true/false of the condition evaluation for each cell is based on a relative reference?
i.e. in cell B2 'TRUE' would be
=AND(B2="X",ISNA(MATCH($A2&"."&B$1,LookupList,0)))
whereas in cell B3 it would be
=AND(B3="X",ISNA(MATCH($A3&"."&B$1,LookupList,0)))