Perhaps we could have two sliders, one for skin weathering (chipping off of colour) and one for operational traces (oil, exhaust smoke traces, ...)
and no, the chipping does not look good. Looks too random. Chipping imho would occur where there are fine mechanical stresses such as ppl standing and walking or by stones projected from the ground during take off and landing.

Some natural chipping may occur due to temperature falling and rising but likely this will occur predominantly on the edged of the skin panels.