It's pure speculation, started earlier in this thread and perpetuated by "interpretation" of the specifications on pages 144 and 145 of the 807/RC180 Instruction Manual. The wattage per channel is listed as "minimum per channel"...135W for the 807 and 110W for the RC180....but it can be more when spec'd that way. However, just below, the "Dynamic Power" specs are exectly the same between the 807 and RC180 at 150WPC at 8 ohms. All of the other amplifier specs are exactly the same....line for line, word for word. Under "General" the power consumption for North America (the RC180 is only available here) is exactly the same at 8.1 Amps and the overall unit weights are 39.7 pounds each.
Generally, a manufacturer can make better use of R&D money by having high degrees of parts commonality between similar products....especially products that can be pre-assembled in sections....like power supply and amplifier. Redesigning for lower pricing requires a LOT of cost cutting and component change to justify the investment in R&D dollars and it's usually better to just make statements that differentiate products with exactly the same components...and then spec them differently, label them differently and avoid royalties where possible like leaving off Windows stickers, moving the stickers to the top of the unit instead of the face, etc.. This positions them differently in their respective marketplaces while allowing the factory the luxury of having common, on-the-shelf, interchangeable parts so they can quickly build one or the other model based upon real orders versus the very often completely wrong market demand forecasts.
So, it's a guess at best, but an educated one that makes sense.