Lets talk about document authentication from principle point of view. It is not only about DV, birth certificate, Ethiopia or US. Any document obtained locally in one country should be validated (authenticated) by MoFA or its equivalent before it is used in another country (Embassies are small versions of other countries). Thus the fact that a CO didn't ask for authentication at an interview of Mr/s. X should not be considered as a norm, another CO or the same CO who have a doubt about the document my ask for authentication. Note that, you can not argue saying "common Mr/s CO you didn’t ask Mr/s X for this document ...", no way!!
Let me tell you a simple case of a need for authenticated birth certificate for one of my family members (one out of five members). As I mentioned here in this forum a couple of times, one of the certificates of my children has a different naming format due to the time and place it was made.
Name: X Y
Father's Name: Y Z
Which requires the CO to use some logic to get the name as X Y Z because all the rest have the name with this format. We have to sweat a little bit to convince the CO it is genuine, thanks to the authentication which we already have at the back of the paper. The CO asked "why it is different?". As I even have never noticed the difference before, it was a sudden question, "dubida" in Amharic. When things go smooth, yes, the CO my not ask you.
You see how the forum is doing its best to convince you, that is why we say it is the best group. In fact, I didn't get why 150 Birr (7$) matters compared to the risk. On top of this, as we learn from this forum, AP is not good when it comes in late months like June. You will be the one who bears the risk about AP. My brother, why invite AP and and even think of going back again. Lastly, better to avoid "mikerew mikerew ..." in Amaharic.