The Price of WDM-PON
Whether they're cheating or not is up to you: ADVA is measuring costs that reach all the way back into the data center, whereas most PON budgeting only tracks from the optical networking unit (ONU) to the optical line terminal (OLT). And I suspect a lot of the savings will come from operating expenses.
ADVA's arguments are written up in an article for the special Institute of Electrical and Electronics Engineers Inc. (IEEE) magazine for OFC/NFOEC. You'll get a copy in your show bag, apparently.
— Craig Matsumoto, West Coast Editor, Light Reading