I haven’t tried using that, but I would always take the battery indicator reading with a bit of salt. I’d say it’s 95% accurate but not perfect. (Source: been repairing iPhones for a while). iOS 17 may also have some bugs there since it’s a newer feature. May be worth reaching out to apple directly if you’re able to replicate that often enough.
That said, I have had days where my battery will last until the next without an additional charge, but have had others where I will have to charge it sooner than expected too.
I have the same model iPhone; 15 Pro, 512 GB
Hope that helps