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