Can Per Diem be calculated by simply entering number of days as opposed to a date range?

Summary: Setup Per Diem policy based on a daily rate and expense line only gives option to enter a date range. Has anyone set this up so user would simply enter the number of days for the period and not the date range?

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Code Snippet (add any code snippets that support your topic, if applicable):