The theme to me is that the show is so producer driven in what they want the audience to see or the outcome to be and maybe, just maybe, the Producer (i.e.,Rebecca) has decided who the F1 will be and it is not the one Jason wants. The theme this season from what I've seen is that Jason is doing things differently than in previous seasons, such as sending one more girl home than is traditionally done, having an at home date while Ty is asleep, having Molly spend the entire night with him.
Maybe his anguish at the end is being forced to chose the one that TPTB and not the one who really has his heart...hence the conversation with Deanna. IDK if any of this makes sense. After reading thousands of posts with so many different theories RS has really thrown a wrench in all of this!