Absolute Dates For fixed report dates, use Absolute Dates.
Example: If the Period is selected as Single Month for August 2022, the Schedule report will be ran for the month of August 2022. Annual Time Series always use Absolute Dates.
Relative Dates For report dates relative to the time the report is run, use Relative Dates. Relative Dates are more useful for saved or scheduled reports.
Example: If the current calendar month is August 2022 and you've selected Period as Single Month and enter a 2 month offset, the report will be for the travel period of October 2022. If the current calendar month is September 2022, the report will be for the travel period of November 2022.