Haha, thanks for the breakdown kind stranger!
You are almost correct, at night 5, she already starts at 18 / 20, and increases past 20 as the night progresses (max 21), making her appear on screen more. but there is a seperate meter that increases whenever the player fails to catch her. If that goes over a certain amount, you automatically lose, but it goes down dramatically when the player does catch her.
That being said, I will lower the difficulty across nights 4 and 5 so everyone can access the rest of the scenes. :)