Yeah, the thing is just, you have to take into account that you're also using resources to create the storage element, to create the storage technology and to create the pattern itself. The fact that the researchers placed molecules (and thus complex multi-atom structures) onto the storage device (the electrolytic copper plate) means that the storage density has to be calculated by dividing the number of bits by the number of elements used to store that bit. I'm fairy certain this is smaller than 1 bit/atom. If you can just place a single atom on a surface, it doesn't mean you have a storage capacity of 1 bit/atom, because the surface your placing the atoms on is also made of atoms, atoms you forgot to count.