In a weaker gravity field with a low sample frequency the algorithm does indeed appear 1:1. The complexity arises once a peripheral second gravity field can no longer be ignored or a certain noise threshold is passed.

The equation ends up looking something like this: https://slack-files.com/TEGQB8GNS-F01UU5FMKRR-820b186081

Once you start thinking about it in terms of the definite integrals of a piecewise function you'll see where the weights would be applied in more extreme situations.