How do you calculate a proportion? If 200K out of 850K BTC have been found, then you need to divide the first number by the second one and get .235 or 23.5%.
Perhaps I did not get my point across yet.
Joe Coiner deposited 100 BTC into MtGOX when they were worth 50$ each. Since then, he traded them with such skill that, when MtGOX collapsed, he thought that he had 1000 BTC in his account, which at the time were worth 800$ each.
Bill Bitter, on the other hand, deposited 1000 BTC at the same time as Joe, but then traded so clumsily that he belived that he had only 100 BTC left at the end.
By method X of computing claims, Joe's claim is 100x50 = 5000$, while Bill's is 1000x50 = 50'000$. So Bill will get 10x as much as Joe from Mr. Kobayashi.
By the other method Y, Joe's claim is 1000x800 = 800'000$, and Bill's claim is 100x800 = 80'000$. So its is Joe who will get 10x as much as Bill.
Method X was used by the US courts when processing the claims of Madoff's victims, and someone claimed that it is the standard procedure in japan too.
So, obviously, the first thing you all need to do is find out whether Kobayashi will use method X, method Y, or some other method.