B31.3 has a single value W. CAESAR II breaks that down into two values WL and WC - WL refers to longitudinal and spiral welds and WC refers to circumferential welds that join piping components. WL is mandatory while WC is optional - that's why we have two values in CAESAR II. WL is used in evaluating the wall thickness and WC is used in evaluating sustained (bending) stresses. If you want to see a change in the allowable stress, you should be working with WC. It works for me (see illustration). If it does not work for you please file a ticket with Smart Support.