Brandon, the first point is that there's no such thing as "RMS" watts, despite some use even by manufacturers. RMS, which is a special type of average calculation you're probably familiar with in your work, applies to voltage, which varies between about +/- 170 volts, with an RMS value of about 120 volts for power in N.America. A watt, however is a fixed amount of power and isn't subject to an average. A correct term for the legally required(by FTC regulations)power rating is continuous power, and it has to be measured for five continuous minutes.
Even that HTIB system has to comply with the FTC regs and show its continuous per channel FTC rating in its specs. The advertising which you saw isn't that, but appears to be adding together the meaningless peak power calculation(at 170 volts double what it is at the RMS value of 120 volts)of 180 watts per channel for the five speakers and 200 for the sub. At a typical distortion rating under 1%, the number might be on the order of 50 watts per channel.
