The statement that accurately reflects the concept of a Significant Audit Difference (SAD) nominal amount in the context of adjusting materiality is:

The amount we select for our SAD nominal amount has an effect on setting scopes and thresholds.

When the planning materiality (PM) is lowered during an audit, it may require a corresponding adjustment to the SAD nominal amount, as this amount is typically linked to the materiality level and influences the determination of the scope of audit procedures and the tolerable misstatement threshold. Communicating such changes to those charged with governance is also important for transparency and maintaining audit quality. However, there might be situations where designating the SAD nominal amount at a percentage lower than 5% of PM could be appropriate, depending on the specific circumstances and professional judgment exercised by the auditor.