Base interface property not bound in MVC view

Question

I have an interface IProduct : IAuditable

public interface IProduct : IAuditable
    {
        string Code { get; set; }

        string Name { get; set; }

        string Description { get; set; }

        ProductItemsList Items { get; }

        ProductType Type { get; }
    }

Where IAuditable is defined as:

public interface IAuditable
    {
        DateTimeOffset CreatedOn { get; }

        int CreatedBy { get; }

        DateTimeOffset ModifiedOn { get; }

        int ModifiedBy { get; }
    }

In a view that is bound to an enumerable of IProduct,

This works: (btw ReSharper tells me to remove the cast)

@Html.DisplayFor(model => ((IAuditable)model.ModelObject).CreatedOn)

But this fails:

@Html.DisplayFor(model => model.ModelObject.CreatedOn)

(with error "MyProj.Products.IProduct.CreatedOn could not be found")

Can someone explain this to me. It's Friday afternoon so I'm probably being stupid.