Is there a way to limit expenses going to audit due to violation based on low values?

Summary: We appear to be getting a lot of low value expenses (less than £50) that have triggered violations of the expenses policies and therefore have trigger an audit. Is there a way of stopping violations triggering an audit if they are £50 or less, without changing the expenses policies?

Version (include the version you are using, if applicable): We are currently using 24a, but will be moving to 24b in June.