Three dates can compete
Submission, assessment and approval may occur in different tariff periods. The governing date is not safe to assume, particularly where an authority’s schedule includes transition provisions or the application was returned and resubmitted.
Before recalculation, record the date shown on the assessment, the schedule edition used and any stated effective-date rule. If correspondence names another basis, preserve it as evidence rather than silently choosing one.
Build a small tariff register
For each schedule, capture its title, authority, effective date, source, retrieval date and file hash or controlled filename. Note whether annexures and category definitions were included. A fee table without its definitions may not support a reliable classification.
Treat amendments separately
An amended area or declared value may produce a supplementary assessment, replacement assessment or credit. The sequence matters. Testing only the final total can conceal a duplicated original charge or an unapplied credit.
Report uncertainty honestly
Where the effective rule is ambiguous, calculate the difference under each plausible version and refer the interpretation to the appointed planning or legal adviser. The auditor’s job is to make the financial consequence and evidence clear.