Your everyday age usually counts completed years since birth. Many Zi Wei Dou Shu charts use nominal Chinese age: one at birth, then another year at the chosen annual boundary. The difference is not always one.
A concrete example
Someone born in December 1995 is still 29 after Lunar New Year in 2025, before their December birthday. Under a Lunar New Year nominal-age convention, the chart can show 31. No birthdays are missing; the two labels count differently.
Births near a calendar-year boundary need extra care. Check the chart's year convention rather than blindly subtracting Gregorian years.
Cycle ranges need the same age convention
A ten-year cycle labeled 24-33 should be read using the age system that produced it. Comparing your completed age against a nominal-age range can put you in the wrong cycle near a transition. The starting age and the direction of progression are separate calculation rules.
When checking an old event, use its calendar date whenever possible. October 2024 is less ambiguous than age 29. Record the selected year, the displayed age, and the cycle range together. An age-label difference can explain why two displays look different; it should not become an excuse to count several neighboring years as the same prediction.