When specifying the time in a specific number of units, note that for consistency, "month" is defined as 30 days and "year" is defined as 365 days. "Days" refers to 24 hour periods, not calendar days. The units of time that you select are subtracted from the time that you click Finish to import the data to give the start time. For example, if you select 2 months, the time period will be the 60 days (24-hour time periods) immediately prior to you clicking Finish. If you click Specify a time interval, the Start time and End time will be automatically set to match the run into which you are importing the resource monitoring data.