Talking through sample size with materiality already set
Materiality is not a substitute for sampling parameters. Once performance materiality is fixed, you still choose confidence level and tolerable misstatement for the specific test.
A useful meeting format: put the population book value, expected error, and proposed method on one page. Ask the engagement partner which assertion carries the most concern this year. That answer often changes stratification more than it changes the headline materiality figure.
Document disagreements. If the partner prefers a smaller sample for deadline reasons, record the residual risk and any compensating procedures. Silent compromises are what quality reviewers later reconstruct from email threads.
For inventory counts in Taichung warehouses, physical observation constraints may force sequential sampling or location-based strata. Write those field limits into the plan before the count date, not after.