I'm not sure if anyone else mentioned it, but I think this is just what happened right before the final chapter. That is, this was to provide a bit of context as to why they were living at the beach and why he was cooking since sunrise without a job. He's trying to get better at cooking so he can run that cafe that he said he would while also looking for alternative work in the meantime. Pretty sure the final chapter is still the official ending where they go back to help her out, but I doubt he plans on going back to being a hitman for good. I'm guessing the two of them will go back home after they finish that last job, with the hope that it will truly be the last job they have to do.
Just thought I'd give my 2 cents on the matter since some of the other comments suggest people think this is an alternate ending, which I personally don't believe to be the case.