Re Chimborazo: I would assume that's cos the earth is flattened at the poles and bulges out at the equator.
From
Wiki Chimborazo article:
The summit of Mount Everest reaches a higher elevation above sea level, but the summit of Chimborazo is widely reported to be the farthest point from Earth's center (Senne 2000, [5]), despite a possible challenge from Huascarán.[3] Chimborazo is one degree south of the equator and the earth's diameter at the equator is greater than at the latitude of Everest, nearly 28° north, with sea level also elevated. Despite being 2,581 m (8,568 ft) lower in elevation above sea level, it is 6,384.4 km (3,968 mi) from the Earth's center, 2.1 km farther than the summit of Everest.[4]