If you detune, you're unbalancing the string vs spring tension, so you need to adjust the tremolo springs accordingly.
Detune the guitar and the bridge tilts back, right? Loosen the springs by unscrewing the trem
claw screws a small amount to compensate. Retune the guitar and keep making small adjustments to the screws and retuning until the bridge baseplate is level with the
guitar body.
See IbanezRules.com tech section for more details:
http://www.ibanezrules.com/tech/setup/index.htm