this is nothing new : just excerpts of his interviews this week-end.
He just said he's exhausted, goes on holiday now and doesn't know if he plays Shanghai or not or if he cares about end of year number 1 or not, he has to rest first and think about it, "he has to look at the bigger picture" as he says.
I also think that he has in sight his exho trip in South America in december which promises to be exhausting as well. When he planned that, he probably didn't think he would be in contention for number 1.
That's all, I also think this feeling of exhaustion is the reason why he wondered about playing Davis cup or not 10 days ago.
We are not sure at all to see him in Shanghai, that's all you can say. Even though Rolex wants him to go there as they're Shanghai's partner and even though not going there, he might miss the 300 weeks at number 1 and nearly say good bye to his chances of finishing the year as number 1
About Davis cup, what he says here is what he has always said about Davis cup for him. Have pleasure with the team, and look round by round (anyway Davis cup has always been a competition like that where you have to see and take opportunities when they're there)
PS : Fed also said recently that people underestimate the impact of his family life, it also takes his toll on him and he doesn't want to sacrifice it at all.