ADP/ACP question

Plan sponsor fails ADP/ACP testing for the 1/1/2024 to 12/31/2024 plan year and refunds are issued to HCEs on 3/1/2025 (refunds issued by the plan's recordkeeper).

On 4/1/2025, the plan sponsor realizes that they mistakenly approved the wrong test and intended to rely on a permissively disaggregated ADP/ACP test (disaggregating otherwise excludable employees). The permissively disaggregated test still failed, but had better results and less refunds to HCEs.

Any idea how the plan sponsor goes about this given that refunds have already been issued and cashed? If they intend on relying on the permissively disaggregated results, then are the original refunds deemed impermissible distributions? Do they try to collect the overpayments from the HCEs by following the EPCRS/Secure 2.0 overpayment guidance?

For example - assume HCE Jane received an ADP refund on 3/1/2025 in the amount of $1,500 and cashed the check. But, based on the results of the permissively disaggregated test, her ADP refund was only $800. Does the plan sponsor follow the overpayment guidance in terms of dealing with the $700 "overpayment"?