Sorta don't understand what you exactly asking. There are still lots of points to gain with them right through to the end in chapter 9. I hope you didn't sleep with any other girls and I mean any that's gonna cost you points also try and spend same amount of time with each of them during events. You will have to figure which events to go to to have time spend about the same or you will loose more points for one of them in chapter 9.
There are scenes that you can unlock in each chapter. Most of them are a single scene but some of them have two steps - so you can get 50% of the scene or 100% of the scenes.
As far as I am aware, what scene you get is only determined in that chapter (whether you get 0%, 50% or 100%). It may well depend on what has happened in previous chapters but it is never retrospectively modified based on successive chapters.
If you don't get 100% when that scene plays then it is because of something that has happened up to that point.
I've only got 50% so clearly I have missed something previously but no idea what that can be.