Different decade starting ages may reflect different chart inputs or display conventions.
The Five Phase Bureau helps determine the starting age of decade cycles. If two apps show different bureaus, compare birth conversion and Life Palace stem and branch first. If the bureau matches but cycle direction differs, check the separate direction rule. Record both apps' settings before interpreting any decade.
Compare the Life Palace stem and branch, bureau, decade direction, and age convention. Resolve calculation differences before interpreting the decade theme.