BJ - don't mean to be argumentative but, please check facts before you post.
My annual UK insurance policy has a clear clause that says you are insured up to the depth that you are certified to or a maximum of 40 metres, maybe US insurers are different.
Padi also states on its website "Open Water Divers can plan and execute dives with a certified buddy or dive professional to a maximum depth of 18 meters/60 feet." that feels a little bit stronger than a recommendation and if you are diving with a PADI facility I would expect them to enforce the limits that divers are trained to dive to or I would go elsewhere