Welcome to the wonderful and obtuse world of coffee.
Unfortunately there is no real reliable single answer to your question.
Some coffees drink well after just a few hours resting (Rich reckons Sumatran Mandeling is very interesting after just 2 hours) and some need a number of days to reach their potential.
I hardly ever have any of my coffees last beyond 14 days. In general I find most of them are pretty good between 4 and 10 days, but there will always be exceptions.
As for the 40 day thing, seems a little high for snobs like us, but perhaps Fresh_Coffee (an actual commercial roaster) might have a comment there.
It reminds me of the story I heard regarding peanut M&Ms.
A friend was working at the factory in the states where they made these. There were large tubs available for the workers to help themselves in the break room. He tasted some peanut ones this day and was blown away by how nice they were. He commented to a colleague and was told "Yeah, theyre fresh. Just made yesterday".
Mate said "Why have I never tasted any like this from the stores?"
Reply - "They are aged on site before being shipped. Its better to present a consistent flavour to the masses. After 3 weeks, they all taste pretty much the same."
Perhaps that is the theory with aging the coffee.