The panel shall issue its decision within 15 days after the receipt of
the petition provided for in section 269b.310 or by the end of that period
shall announce that it will require briefs by the parties. Such announcement
shall specify the requirements as to contents of the briefs, and the time for
submission, which shall vary to meet the circumstances of the matter
appealed. The panel, at such time, may also require oral argument or the
production of evidence or may so order oral argument and/or the production of
evidence after examination of the briefs. The panel shall issue its final
decision within 20 days after briefs have been filed, evidence has been
produced, or oral argument has been conducted.