The importance of sleep in flushing?

This study dates back to 2005. With it came some questions that made me believe it to not be true.

The Lancet suggests the stones are a mixture of Oleic acid and Citrus.

Why does the presence of sleep determine the success of Liver flushing? In situations when I've swallowed a cup of oil and failed to sleep, I did not produce any stones. If What the Lancet suggest were true, why does sleep or even a two hour nap play a leading role in stone production when the digestive system is active in a sedated or conscious state.
So shouldn't stones be produced either way if the Lancet was correct?

If the Oleic acid and citrus constitutes the stones, why is there no cooking oil scent or citrical scent left behind in the stones?

Link to study - http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2805%2966373-8...
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