I was charged when I downgraded back to gold, sent them SM and got this response:
Dear Mr. ......,
Let me check this for you right away.
I see that your Card account was upgraded from Business Gold Rewards to Business Platinum Card on March 29, 2013.
Due to this, a pro-rated annual membership fee of $187.50 for the Business Platinum Card was assessed on your account. Also, a pro-rated credit ($52.08) of the annual membership fee for Business Gold Rewards Card was issued.
Later on April 09, 2013, your Card was downgraded to the Business Gold Rewards Card. Therefore, the annual membership fee will be adjustment once again.
In order to assist you in this matter, I've submitted a request to suspend the membership fee of $187.50 for the Business Platinum Card.
I assure that you don't have to pay this amount until the annual membership fees have been re-adjusted.
I hope this information helps. Should there be anything else that we may assist you with, feel free to contact us again.
We value the relationship built with you since 2001 and wish you an excellent day ahead.
Sincerely,
Umang Gupta
Email Servicing Team
American Express Customer Care