Question regarding NBME scoring!!!

[Doc4Step1]

So I always wondered how NBME and real exam are scored.Which obviously no has answered yet.: But this time I have the same question in a different way. One of my friends took NBME 7 online with extended feedback . He made 71 mistakes and his score was 238 in NMBE 7. I had read somewhere that if u multiply the number of ur right answers by 1.4 . Thats your score. So if we multiply his right answers 129 x 1.4 = 180.6 . Now I don't understand why is it so? Either this calculation is totally wrong or exam is scored in a totally different way.

Can one score 238 with making that many mistakes? That's like 64% right and 36 % wrong answers.

Some explanation will help. Just curious you know

Thanks

[preet_doc4]

I have also seen this formula floating around. But am not sure if it is (completely?) accurate.
In my understanding, your actual score is likely to depend on not just the %age correct, but also which questions you got correct, what options did you pick for the questions you got incorrect (completely wrong answer, or close-by answer).
This is how I have begun to understand things, based on my experience over the past few months. For example, I got 100 correct on one exam, and my score was 192, which is not close to 140 predicted by this formula.