Good day! Are you referring to the Unbilled Detail and Aging report.
Under the reporting option of this report, you have 3 Aging date options:
Select the date from which the aging data is calculated:
Today's Date — Age transactions based on the current date.
Period End Date — Age transactions based on the last day of the current accounting period.
Specific Date — Age transactions based on a date you specify. Enter the date, or click the calendar icon and select the date.
If this does not answer you question, I would suggest submitting a support ticket via the Submit Case or Chat options.
I hope that helps.