I guess if the T required 4 weeks notice and I didn't want to go to 4 more sessions, I would give notice and do just one last session, but I would cancel my appointments for the next 3 weeks, then do the last session a month after I gave notice. That way I would fulfill the "4 weeks notice" requirement but only have to pay for one last session. Also it would provide a cooling off period and time for the client to think about it in case they wanted to change their mind. I don't know if these Ts think money grows on trees or what. If the client wants to do 4 closure sessions, then great, but it seems inappropriate to require everyone to cough up money for 4 sessions if they want a briefer closure.