Macpherson in *a survey of homogeneous structures*, states that there are many $\aleph_0$-categorical structures which are not homogeneous. Here homogeneity is the ultrahomogeneity that is defined as every isomorphism between two finite substructures of a structure $M$ can be extended to an automorphism of $M$. $\omega$-homogeneity is ultrahomogeneity on a countable structure.

I am confused on this because it is well known that a $\aleph_0$-categorical structure is both atomic and countably saturated, and both atomic and countably saturated structures are $\omega$-homogeneous. This actually means that a $\aleph_0$-categorical structure is ultrahomogeneous. Where is wrong here?