You are absolutely correct. The A8-7600 is slightly better at stock than the A10-5800K at stock. However, if you overclock the A10, it can surpass it in performance. It also seems to have a slightly better IGPU than the A8.
So it really just boils down to this. If you wanna overclock, go with the A10. If you don't want to overclock, go with the A8.