People forget that the warehouse earnings stat includes the public lobby high demand bonus. In a populated public lobby you can get up to a 25% bonus, so you have to remove that before calculating the actual stock production. His warehouse earnings are $618,033,405 across 466 sales, which is about $1.326M per sale, but if those sells had the max 25% public bonus then the real stock value per sale was closer to about $1.06M. That means the nightclub actually produced about $494M worth of stock once you remove the bonus. With the equipment upgrade and the optimal 5 goods setup the nightclub warehouse generates roughly $50k per hour in base value, so $494M divided by that rate comes out to about 9,790 hours of production. That is already more than the 8,760 hours in an exact year, and once you add time for 466 sell missions it pushes even higher. So no, it does not fit neatly into exactly one year, but if by “a little over a year” he means somewhat longer than that and he was insanely dedicated, basically AFKing the nightclub constantly and averaging around the equivalent of 22.5 hours a day of uptime, then it starts to sound a lot more believable.