I don't remember exactly where I first heard them, but that is the pronunciation recommended by the Dozenal Society of America.

http://dozenal.org/

They also recommend for large numbers:

• 10 = do = dozen
• 100 = gro = gross
• 1,000 = mo = megagross
• 10,000 = domo = dozen megagross
• 100,000 = gromo = gross megagross
• 1,000,000 = bimo = double megagross

and so on.