Vgcharts estimate retail with good educated guess based on so many official charts we get apart from hard numbers. Same can be done with digital sales. Right now sales of games don't make any sense and in future digital is only going to become more common. I have stopped looking at Vgcharts because of this reason. Its time to estimate digital sales to get near to actual unit sold. Vgcharts was never about being 100% correct but right now its not even 50% correct.