If a decrease in the value of the decrement at yₒ were essentially produced by previously keeping the wire oscillated for some time through a smaller range, much more should there be a decrease if it were previously kept entirely unoscillated.
Source: wiktionary
A disadvantage is that one is averaging over two different baselines so that if only the long-distance sample has oscillated significantly the result will be diluted by the unoscillated sample from the shorter baseline.
Source: wiktionary
The reconstructed VỤ CC energy spectrum from the Far Detector data compared to predicted unoscillated spectrum and best-fit oscillated spectrum.
Source: wiktionary