@FrankCastle from looking at your post # 207 it seems they did spell it out for you. If there was going to be another fee, it would state it on the document you are signing.
I have sold 8/9 contracts in the last year - once I was at the stage where monies had been paid there was no more charges.
In my case I paid the $500 up front when I submitted the form.
That covered paperwork prep and lawyers office for transfer.
In your case you paid upfront to start the process. I would be surprised if there was an additional $500.
They already got their pound of flesh.