My knowledge of Oracle is limited, but I understood that a Materialized View was always accurate to the second, just as an Indexed View always is in SQL. If he used something analogous to an Indexed View why did it need to have a time lag?

I will say I have done something similar in arranging for long running reports to be precomputed at night, but that was always to avoid the write performance reducation that would have come from putting those in an indexed view that would have been constantly current and always up to date.