Just a heads up: the RE4 kaitaishinsho guide points out that Chapter 5-4 ends in the cutscene where Ashley and Leon get their Plagas removed. The boss fight is in a different level called "Final Chapter".
Thanks for the note. The Final chapter has 7 unique cutscenes + ending of the whole game. I suppose the cutscene article must be named Final Chapter - scene 1, Final Chapter - scene 2, etc. Am I right? :)