A change from five working days to three does not automatically mean the same number of leave days should remain untouched. Holiday entitlement is usually expressed against the days in the working week, so the pattern matters.
Record the effective date
Write down when the schedule changed and how many days were normally worked before and after it. Hours per day may matter to pay, while days per week are central to understanding how leave is booked.
For irregular shifts, collect rosters over a representative period. Avoid converting the whole year with one rough average if the pattern changed at a known date.
Test the employer’s figure
Ask which full-time reference was used, how fractions were handled and whether leave already taken was allocated before or after the schedule change. These questions often expose a simple input error without turning the discussion into a dispute.
Contractual days above the statutory minimum may have their own calculation wording. Read the clause alongside the employer’s policy rather than treating the portal total as the source rule.