You gotta be the king of stupid..
If Nelly sold 10 million cds for $10 each that is 10m
If Biggie sold 5 million of a double album at $20 it's 2m because you sold 2 units.
You ever go to a supermarket and buy a stick of deodorant for $5 and they have the value pack of 2 for $9.99.. It's the same shyt. You're buying 2 units in one. How hard is that to understand.
That is not how it works. The units sold is the units it sold. Soundscan does not double the sales. The RIAA does that for certification purposes. A double album that is certified diamond still only sold 5 million copies.