Chapters 13 and 14 were revisions. Certain things needed to be tweaked because of new events, but the skeletons could remain essentially the same. Chapter 15, though, will be new material.
A lot of what used to be there will have to be dumped. But part of being a writer is the willingness to “kill your darlings.”
I don’t ever quite kill them. Instead, I transfer them for temporary safe-keeping to a separate file with other sections that have been cut. I don’t usually go back to bail my words out of prison, but it has happened often enough for me to know that this is a good thing to do.