Clear method does not clear owned settings

[Falc]

I am using this bundle in a project to define a global shipping_cost setting. Since an admin can set a "discounted" shipping cost to specific customers, the setting has ALL scope. This way I can do something like $settings->get('shipping_cost', $user) to retrieve either the specific (customer) shipping cost, or the global one.

The problem appears when an admin wants to remove the specific shipping cost from the customer. It does not get deleted from the database. Instead of that, it is set to the same value as the global one. This creates a problem when the global value changes.