A type scale you can defend
Every size on the page comes from a role, so one setting changes the page rather than one heading.
Most type scales are a list of numbers somebody liked. That works until the day you want the whole page a little larger, and you discover the numbers were never related to each other at all.
A scale is defensible when every size is derived, and when each size belongs to a role rather than to a place. Not "the h2 on the article page" but "a section heading" — because the moment a size is attached to a location, the same heading in a second location gets a second number, and the two drift.
A ratio, and the honesty to break it
Pick a ratio and generate from the body size. A minor third (1.2) is quiet and works for text-heavy pages; a perfect fourth (1.333) is dramatic and runs out of room quickly on a small screen.
Then allow yourself to round. A scale that produces 27.65px is a scale nobody will follow, and the rounding is not a compromise: the eye cannot tell 27.65 from 28, and the person maintaining the page can.
Leading and tracking travel with the size
The mistake that survives longest is treating leading as one number. Large text needs proportionally less leading than small text, and display sizes usually want negative tracking while small sizes want a touch of positive. So a role is not a size, it is a triple: size, leading, tracking. Set all three or you will set them by accident later.