Strange the Svbony doesn't make a 8x42 ED- would have though that would come before a 8x32. Pat
I doubt that Svbony make any of their binocular products any more than Bushnell, Celestron, Meade or Opticron make their binoculars. SV are most likely solely a marketer who buy their optics from OEM manufacturers in China. Nothing wrong with that as long as they religiously monitor the quality of the product.
Is it possible that they are using the same eyepieces in the 8x and 10x models and the higher magnification is simply the result of a longer focal length? Nikon does this with its E2 8x30 and 10x35, everything rearward of the prism shelf - metal housing, prisms, focussing mechanism and eyepieces - is identical and the only difference is a longer screw-on barrel and the objective lenses. This approach offers considerable manufacturing savings.
They may also have decided that there isn't sufficient market to justify offering an 8x42. Most non-birders are under the misconception that the more magnification the better and if they're going to carry a big bin it ought to be a 10x or above, and at this price point most buyers are neither birders nor astronomers. Even for many birders the higher weight and reduced FoV of the 8x42 causes them to choose the 8x30 instead, whereas at 10x30 the reduced eye relief and brightness pushes them towards the 10x42 format.
They also market an SA202 10x42 binocular which is listed at $US31.99. Make sure you order the correct model and that's what you receive.