returning multiple IdP entityIDs to the SP

In section 2.4 of the "Identity Provider Discovery Service Protocol
and Profile," it says "The discovery service interacts with the
principal via the user agent to establish one or more suitable
identity providers" and "The discovery service redirects the user
agent back to the service provider with the selected
identity provider(s)," which suggests that multiple IdP entityIDs may
be discovered.

Then in section 2.4.2 it says:

"The discovery service MAY rely on saved state, such as HTTP cookies,
to determine the appropriate identity provider. If a single cookie is
used, it SHOULD conform to the name and format specified by the
Identity Provider Discovery Profile in section 4.3 of [SAML2Prof]."

which also suggests that multiple IdP entityIDs may be stored. In
section 2.4.3, however, it suggests that the value of the entityID
parameter is a single IdP entityID. Is this true? Is the intent of the
protocol/profile to return a single IdP entityID to the SP? If so,
why?

Tom