I have already written the first book in a series that could be a stand alone. Now I'm editing and I'm writing the sequel. In the sequel, I've come across a scene that will reference something that happened in the first book, though it didn't make sense when it happened (now it does). But I have a dillema: Do I remove the scene so that if I can only sell the first book, it makes more sense (than leaving the scene in), or do I keep it so that if I can sell both, everything fits together well?