Transport elements in CPP & CPA

We are setting up CPP's and CPA's for synchronuos ebXML communication
and are wondering about a portion of the spec (ebXML CPP/A
specification v2.0 chapter 8.4.24) where it says.
"A Transport that contains both TransportSender and TransportReceiver
elements is said to be bi-directional in that it can be used for send
and receiving messages.
If the Party prefers to communicate in synchronous mode (where replies
are returned over the same TCP connections messages are sent on; see
Section 8.4.23.1),
its CPP MUST provide a ServiceBinding that contains ActionBindings
that are bound to a DeliveryChannel that uses a bi-directional
Transport."

but later in 8.4.38.1 it states
"For a synchronous response, the "response" endpoint is ignored if
present. A synchronous response is always returned on the existing
connection, i.e. to the URI that is identified as the source of the
connection."

Thus in order to have a synchonous response you have to include an
TransportReceiver with an endpoint that is explicitely never used.
 Wouldn't it be better to not include the TransportReceiver at all and
thus show directly in the CPP that the endpoint in TransportReceiver
is never used.
As it is now you have to include an endpoint even for an
implementation where no incoming traffic is possible or allowed except
as a direct response in the outgoing session.

What is the purpose of this?  And is this how the specification should
be or is this an error that should be corrected?

---
Sigbjorn Berntzen
BAR Consult AS