The Company I work for wants to be able to turn off certain mail features on certain days & times. For example, Exchange ActiveSync, MAPI and HTTP only available on Tuesdays & Thursdays from 9am to 5pm (server time). We've already implemented all this with some slight caveats... the HTTP changes kick-in after existing threads are dropped, so we mount/dismount the db to get that done. Our other issue is the Information Store only checks for these type of changes every 2 hours. We want to change that interval to 10 or 20 minutes. We followed the instructions in this technet article: http://technet.microsoft.com/en-us/library/bb684892(EXCHG.80).aspx, and added the Mailbox Cache Age Limit value to the registry with no apparent change. When I read over the article, I think that's the only value we had to change to fulfill our needs. What am I missing?

Im not sure what you are trying to change. That article refers to changing send/receive limits for mailboxes.

BTW, I have found that disabling and enabling mailboxes for various protocols is inconsistent at best as far as timing for when those changes take effect.