When taking advantage of any "big box" agency lower rates/higher perks (which are offered relatively often), make sure you research their cancelation rules. If you book with HAL (or many travel agents), you get a 100% refund (or some form of FCC) if you cancel before the final payment date. Many of the "big box" agencies keep your entire deposit no matter when you cancel (or rebook for a different cruise). For us that's usually unacceptable, especially if the deposit is substantial and the cruise is a long way off.
Jus' sayin'...