I have to disagree about the Charmings getting a full refund for the price of the curse. I would argue that splitting your heart does have a price in itself. It’s likely if one of them dies, they both have to die at the same time now. We saw this idea with Alice and Will on Wonderland. That’s a pretty big risk for the two of them to take.
While this is a good idea, it’s an “if ,….then” situation and you have to have the “if” part first. Let’s face, after this episode neither Charming nor Snow will ever die meaning that Matt’s hypothetical will never come into play. So it’s risk without any real consequence.
I don’t expect the writers to revisit this with Snowing. They have a tendency to leave the arc once it wraps and never mention it again. Think about S3A. So much happened emotionally to those characters and one has even mentioned PP>