How to define an Oem Action in CSDL?

Hello, I'm having trouble reconciling two parts of the Specification in the topic of Oem Actions. I want to define an OEM action for a Redfish resource (not an OEM Resource).

9.8.8 "OEM actions" states the following 
And provides the following example of an OEM Action for ComputerSystem


However, 11.1.5.4 "Action element for OEM actions" provides the following example for a Contoso.Ping action for a ComputerSystem

Note that in this example, no attempt is made to define an OEM ResourceType, instead it uses the Redfish ComputerSystem Resource.
Also, the definition is made in a "Contoso" namespace, while the previous example defined the action in a "Contoso_ABC_ComputerSystem" namespace.

Which leads me to these following questions, given in the form of an attempt to write the schema:

<EntityType Name="Contoso_ABC_ComputerSystem" BaseType="Resource.v1_0_0.Resource" Abstract="maybe?">  <!--Is the OEM Resource needed? And how do we refer to it in the action? And what namespace should it go into? -->

<Schema xmlns="http://docs.oasis-open.org/odata/ns/edm" Namespace="Contoso_ABC? Or Contoso_ABC_ComputerSystem?">

  <Action Name="Ping" IsBound="true">

    <Parameter Name="ComputerSystem" Type="ComputerSystem.v1_0_0.OemActions"/>

  </Action>

</Schema>