It is possible to run an Aged Debtors report as at either a Date or a Period as follows:
In Debtors, select Reports.
Expand the As At Aged Debtors section.
Choose the required report
Summary reports will show the total by customer.
Detailed reports will show transactions, totaled by customer.
Click the eye icon or magnifying glass one.
Enter the required Date or Period criteria, along with any further filters
Click OK to run the report.
Please note that comparing a Period report with a Date one may give different values as they calculate using different criteria.