Marks should know what he's talking about, so I don't exactly doubt him. However, this is what I found on the matter: http://www.cbafaq.com/salarycap.htm#Q13
My personal interpretation:
12 games is 1/6th of the season this year. Beasley is making $13,425,895 this season, of which 1/6th is $2,237,649.17. That is the amount which should be deducted from Beasley's earned salary, and the team books should not include half of that or $1,118,824.58 at the end of the season.
There was another part of the Coon FAQ that mentioned suspended players are docked either 1/110th or 1/145th of their salary, but neither one lines up with the above amounts (maybe they're based on 82-game seasons?). The part I mentioned above from Marks does seem to line up closer, but it's like it was cut in half twice instead of once so I'm not sure where the discrepancy lies between my numbers and Marks' or what I'm missing.
Also: I'm reading that the docked amount on the team salaries is only for luxury tax purposes and not extra cap room though. That part is somewhat confusing to me as to what that means exactly. I think what they're basically saying is that the amount does not create any sort of salary cap exception?