There's room for another three Jaffa Cakes in that box. I know it says on the packet that there are ten in there, and I know it gives enough information to work out the weight of each cake (376kcal per 100g, 41kcal per cake, so each cake weighs around 9.2g), but that box is misleadingly large. They can't use the "contents may have settled during transport" excuse that cereal manufacturers have been foisting on us for decades, either.
Either make the boxes smaller or fill them up and charge us more.