Correct, volts x amps = watts.
Before class D, old school thinking said you needed "beefy" power supplies (plenty of reserve) to provide a commanding grip on difficult to drive speakers, like Maggies. In general speakers are current loads (they respond more to the current provided than the voltage) yet most amps are "voltage sources".
Why not just ask the factory what they recommend? Who should know better? And if they give you an answer you don't like, maybe you should move on to a different brand of speakers.