Just an update to let you know I'm very interested. I'm also still waiting for a definitive answer from Customer Service. 

In the meantime, if you look at the Editor World site, you'll see a tab for "Prices." As you have about 18k words, consider a 3-7 day turnaround, with the cost declining as the time increases. The reverse is also true: sooner is more expensive. So think about your deadline and run some test numbers to see what suits you the best.

As for me, I’ve checked out FDX vs. pdf, and though I’ve not yet dealt with an FDX file, I know what it is and can get a reader/converter. The pdf might be best, as I can review it in Adobe Reader XI, which allows for very good tracking of the changes and comments. 

So please be patient a bit longer.