A paper by Simon WW Manley has claimed that the data from Miller’s ether drift experiments contains a component at the period of full rotation. Ether drift is expected to cause a component at half rotation because the Michelson interferometer is symmetrical on 1800 rotation and no component is expected at full rotation. The author concludes that “unless the advocates of ether-drift theories can provide a satisfactory explanation for the signal component with the period of a full rotation, that component is fatal for any contention that Miller’s heroic experiments were measuring meaningful physics.” We will reveal the origin of that fundamental component based on a new theory of absolute motion. The problem is rooted in the universal presumption that absolute motion is motion relative to the (non-existent) ether which predicts 1800 symmetry. Apparent Source Theory ( AST ) predicts that the Michelson interferometer is strictly symmetrical on full rotation, not on 1800 rotation. However, AST also predicts null fringe shifts for absolute velocities parallel and anti-parallel to the longitudinal axis and this may cause stronger second harmonic component.