Hi Tambc
Yes, your payment is for the four weeks prior to the 17th Dec. I'm not sure what you mean, by is there a cut off date.
Decisions from telephone assessments are taking on average eight weeks to come through, and with yours coming so close to Christmas, it would be surprising if you received a decision before the 17th Jan - but none of these things are set in stone.
BIS
Nothing on this board constitutes legal advice - always consult a professional about specific problems