Value pluralism again

It's reasonable to value patterns that are longer and which occur more frequently.  In Asa H lite Duration(A) is the length of pattern A and N(A) is the number of times pattern A has been seen.  But should these two values be given equal weight and combined as a product? i.e., should the utility of pattern A be U(A)=Duration(A)*N(A) as it is in Asa H lite?

An alternative is to keep Duration(A) and N(A) as components of a vector utility.  Instead of preferring pattern A to pattern B when U(A)>U(B) we might check to see if (Duration(A)>Duration(B) AND N(A)>N(B)) OR (Duration(A)>Duration(B) AND N(A)=N(B)) OR (Duration(A)=Duration(B) AND N(A)>N(B))