Character Transfer Question

My server is dying for our faction's side, so my guild is considering a server xfer for WotLK prepatch. The Character transfer text is fairly ambiguous, and we aren't sure if the transfer limit of 90 days is per CHARACTER or one character per ACCOUNT. Is anybody able to confirm if you can transfer multiple characters on a single account in a short window? e.g. your "main" then your various alts? <3