The start/end times for the Test Request/Response Pair report in the DevTest Portal shows based on the timezone for the setting of the Operating system for the Portal.
Here is the example the screenshot from the Portal which timezone setting for operating system is UTC+9.
However, the start/end times for the exported PDF or CSV files from this report seem to show based on the Coordinated Universal Time like below:
This is a known problem for DevTest Portal.
Release: Service Virtualization 10.3
Please open a support case to get the solution of this problem. CA support will deliver the patch for this problem.