[uddi-spec] subscriptionResultsList in UDDI V3 Subscription API

I am looking through the V3 Subscription API and cannot explain one
thing about it that I don't think has been discussed outside of the UDDI
Consortium's Working Group.  subscriptionFilter is modeled as exactly
one of either of the get_xx or find_xx operations, which I find quite
fitting.  At the same time subscriptionResultsList is modeled to allow
multiple get_xx/find_xx responses per subscription, whereas subscription
can only have one subscriptionFilter.

Can someone please help me understand why subscriptionResultsList does
not use the "choice" model the way subscriptionFilter does?  Is this
related to the lack of adequate development tools support?

Daniel