It sounds like while you have read the Tizzie Hall book, your son has not
Maybe what you are finding is the inevitable meshing of your child's routines with what someone else says he 'should' be doing.
4 months is around the start for most babies to fall into a rhythm or pattern to the day. I would use the book as a guideline and just see where you and your son fit within it.
Not all babies want to be bf every 4 hours, and dreamfeeds don't work for all babies either.