it's in - the intent of the rule is that there be actual race data to support a configuration. A certain threshold of data result in a number without brackets or parentheses. If you can find your boat on the Portsmouth page, you're OK (see
http://www.ussailing.org/portsmouth/pyindex.htm). If you have to do math to get your rating (e.g., a Hobie 20 with a 'chute), there isn't enough data living at US Sailing yet.
Darline Hobock is the tireless driver behing maintaining these multihull ratings seasonally, but she's not alone - there are several people whose names you may recognize that sit on the committee - see
http://www.ussailing.org/portsmouth/committee.asp. None of the ratings or decisions affecting them are made in a vacuum.
If you're sailing a boat with a provisional rating, and you know you want to sail it at your area event, you'll be amazed at how hard Darline will work with you to gather up enough race data to make it happen for you. I've seen it happen! She's amazing! She just wants your regatta results, folks.
Please make your area event - participation at the area level is what allows us to have a meaningful championship each year. Unless we can continue to demonstrate to US Sailing that there are multihull sailors in the world, we'll see the Alter Cup go the way of the Dodo... please sign up and race hard!