The very last thing I worry about when drafting is structure. I suppose I've learned that a story starts out with a character thinking that their goal is one thing only to have a twist or decision point at the 1/4 mark that uncovers the true goal. Because they pursue that goal and believe they're making progress, at about the half way point, everything is going to go to hell in a hand basket because the character runs up against the main challenge of the book and yet the character hasn't yet changed enough overcome that challenge. So they run face first into it. WHAM. Fail. Fall. And have to wander off to lick their wounds. And they have to make another decision. Either give up or double down. So on and so forth.
The problem for me is that I have to throw all of that to the wind when I draft. This is because drafting is slow and difficult for me and I want nothing analytical to pull me out of whatever tenuous drafting space I can achieve. Numbers and divisions and did this decision point happen in the right spot are all worries for a much later date. So I start a draft. No chapters. Just words. Get to The End.
NOW I put on the analytical hat. Now I start looking at over all structure. I go through and arbitrarily assign chapters roughly every ten pages. I'm looking for a natural scene break or place to end on a hook. Some chapters are ten pages, some eight, some twelve. Until rewrites.
As I go through my own dev edits and work through punching up emotion and language and scenes, my arbitrary chapters begin to tell me what they need to look like. Some book keep the ten page chapter convention without issue - most of the SFRs do that (it's easier with only one or two POV characters.) The current WIP, however, has some super short chapters, and one or two long ones. The chapters follow POV shifts because there's an extended cast with several points of view. The book is supposed to be fast, but full of sensory detail and the turned out that the best way to put a reader into a scene was to invite them into each character's world.
Long way of saying that I don't maintain a word count list for scenes or for chapters or for turning points. Structure is a wire frame in my head, yes, but as the Pirates of the Caribbean would say that's, ". . .more guidelines than actual rules." Do I check out that my first decision point happens within the first 25k of a 100k novel? Absolutely. Usually, the earlier the better for me and for my reader. I can get right to the action. Spreadsheets can be great things. Word counts can be great things. But depending on who you are and what your process looks like, they can completely shut you down. The only way to find out is to try them and judge the results. If you are someone who wants to keep things vague and open and full of possibility, consider this your permission slip to learn what structure works for you, store that structure in your muscle memory, and then just draft. Impose logical structure in your editing phase.
We'll be the Ghost Busters of writing: Don't cross the creative/drafting and analytical/editing streams. It would be bad.