I read an interview with the Coens where it was supposed to be 2 different times. They said it was very hard to film that scene because in the book it was made to look like he was a coward and too afraid to enter the room. I think the Coens were able to get the message across pretty well.

That would be the only explanation I would accept, because it would make Chirug not like his character throughout the rest of the movie (and that would be because it was the Sheriff's imagination of Chirug and not Chirug that was afraid behind the motel door).

Hammer meet nail. I think you hit it right on the head. The reason Chigurh is shown to the audience is so we can see what Bell is thinking even though he obviously has never seen Chigurh. He doesn't want to be a coward and not enter the room but is ultimately relieved to find that Chigurh is long gone. The scene effectively showing him feeling over-matched and no longer able do the job the way he feels it should be done.

I really liked the dreams Bell was discussing with his wife at the end; after all the dreams are interesting to the party concerned. To me, they showed Bell felt when his time here was up his Dad would be waiting for him despite his mistakes & shortcomings and he found comfort in that. A few scenes earlier he said he thought God would come to him but didn't, however, Ellis dismisses that by saying you don't know what he thinks and says "whatcha got ain't nothin new. This country's hard on people, you can't stop what's coming, it ain't all waiting on you. That's vanity." Ultimately, Bell is a good man and will be judged accordingly, where as many others in the film will see the opposite end since they only care about the here and now. I also liked the line at the beginning: "A man would have to put his soul at hazard. He would have to say, "O.K., I'll be part of this world."