Universal acceleration theory of gravity posits that the earth is moving upwards at an acceleration of 9.8m/s/s. However, this acceleration is not the same everywhere on earth i.e. higher altitudes show a diminished acceleration. Globe earth theory explains this using the universal law of gravity which is an inverse square law (the further two objects are from one another, the less the attractive force is between them).

How does flat earth theory explain these verifiable differences on earth?