Camera alignment looks great, however. :/
I think it is simply that the smooth white surface is not easily modeled.
I think so too. As mentioned earlier, to overcome such surfaces you can use pattern projection which works very well, unfortunately this is not fully supported with the actual version of PhotoScan and you have to reorder and rename images by yourself. It's time to make a feature request? Also the photo process is more difficult, search the forum for related discussions/ topics.
Karsten