B31.8 VIII has three Code equations and three allowables, whereas the output report only has room for one Code stress and one allowable. So CAESAR II determines the ratio from all three pairs, and puts the governing (highest ratio) values of Code stress and allowable in the report. The allowable shown in the report could correspond to the hoop stress, the longitudinal stress, or the combined (equivalent) stress.

If you can't figure this out, open a Support Request (SR) on eCustomer, specify the exact version of CAESAR II you're using and attach your job file (.CAESAR II).