I don't know all of the answers but I believe I read some about this in Daniel's running formula.
My own personal belief (informed by reading Dr. Daniels and others, not all made up on my own) is that different systems react differently. Stopping completely 10-14 dyas before a race would have serious effects on neuro-muscular coordination (I believe this is the quickest element to train or de-train) and would have some negative effects on things like blood volume and heart stroke volume. I am not sure it would have an effect on the periphery adaptations inside the muscle cells, so maybe that is primarily what it refers to. I'm not an Ex-phys guy, so this could all be completely wrong but it sort of makes sense to me.