"total area under the curve can still be determined with precision" - what? Perhaps - can be approximated depending on the size of your slices.

Isn't this just numerical integration, for which there are libraries in many languages?

Exactly. As I like to say: medics have just discovered calculus. This by itself is actually good, but being completely ignorant of integration is sad. They live in another world.

That’s probably the point of posting it here. If this is the one I’m thinking of, it became famous for being, apparently, an oblivious reinvention of some of the integral calculus.