They probably wanted to cut back on their hours, focus more on theatre side projects, I guess...
I sort of have the feeling that Callen was missing Anna for the past couple episodes, so it made sense to me... During the Christmas ep both Sam & the old friend said the same thing to him... If he finds the right person, he shouldn't let that person go... So I guess he was just following their advice
Yeah, the flashbacks wouldn't have made much sense afterwards...