Zurich American Insurance Company ("Zurich") offers a proprietary "General Liability Supplemental Coverage Endorsement," form U-GL-1345-B-CW (04/13), which is used to modify and, in some cases, enhance coverage terms reflected in current ISO commercial general liability ("CGL") forms. However, form U-GL-1345-B-CW includes one change that can significantly impair risk transfer when used by a trade subcontractor who has promised additional insured ("AI") coverage to an upstream party.