ECO is 2006, BCO was 1982 (This was the first edition and if my memory serves me correctly the Editors devoted an entire page of analysis to this one variation).
Think about it: Chess has been around for 500 years and BCO 2 is 400 pages long. In other words each page of analysis represents the distillation of a year's worth of theory by the entire chess community combined i.e. the Editors are saying that they thought the Berliner Gambit was so important that it deserved an entire page of analysis---and they got it completely wrong!
To show just how little the refutation is known, isn't it surprising that Deep Fritz 14 which came out in late 2013 plays the Berliner Gambit every time it plays the Fritz or against 6.Bf1 in the Ulvestad!
90% of the ideas that I tested with Lev were mine; he merely responded to questions I posed to him. Since we worked through snail mail, it would take months to do analysis it is possible to do in a few hours with a computer.
Even assuming it is true...
I have ideas. Try every move in every position.
Now I will let some GM test my ideas and claim credit for that.
Great idea! If someone had done that 30 years ago, the Berliner Gambit would have been refuted 30 years ago; instead it is the only choice of Deep Fritz 14 which came out in 2013 and is regarded as with compensation in ECO.
If I had followed your advice, I would have refuted the Berliner Gambit, the main line of an early edition of BCO 2 15 years ago.
Your suggestion is actual the only thorough way to do chess theory.
Which year were published those ECO and BCO 2 that you are quoting in some of your posts?