Why Medo-Persia?

The ram which thou sawest having two horns are the kings of Media and Persia.

Daniel 8:20

The prophetic outline of end-time events in Daniel, the first 2 times given begin with Babylon.(the metallic statue then the 4 beasts).

But when this prophetic outline is given a 3rd time, it skips Babylon (even though it is given during the 3rd year of Babylonian ruler  Belshazzar) and begins in Medo-Persia. WHY?
Because it deals with the additional information of the 2,300 days/years prophecy. It's focus is on it's staring point, which began under the Persian, not Babylonian rule.