751—9.4 (8D) Waiver investigation, limited discovery. The commission staff shall commence a waiver investigation upon receipt of the petition for a waiver. The commission staff may make requests for supporting data from the petitioner or propound interrogatories to the petitioner or conduct depositions of relevant persons regarding information possessed by the petitioner relative to the waiver petition. Data requests or interrogatories served by commission staff shall either be responded to or objected to, with a concisely stated ground for relief, within seven days of receipt. The commission chair shall rule on all objections. Depositions of relevant persons must be conducted within 30 days after the petition for waiver is filed unless the parties agree otherwise.