Do you know if platinum is a recent change? On October 2015 Michelle Woofolk provided this response to my inquiry:
_**c. What are the business care percentages for silver / gold / platinum for use in figuring the annual maintenance cost for those who remain on perpetual?**_ Same as today Silver is 21%, Gold is 25% - what's new is Platinum, which is a flat fee of $2000 on top of Gold.