It does not matter which version is your environment. I am unable to understand the reporting process. To better answer your situation we need clear picture, how reporting tool access the incidents or any other form data when it is deleted. I assume data is being copied over to another db for reporting and does not sync with production data when it is deleted. If that is the case then this is weak approach for reporting. Incidents should not be deleted until unless archived and you have storage issue.
Please give us the clear picture of the deletion and reporting.