According to the text of the article, the Benedeks lost $20MM and Reissfelder lost $12MM.
The sums you quote ($656MM and $85MM) are what they sold their companies for, respectively; maybe those numbers are from public records. But, the primary sellers didn't necessarily retain all that money. There were other stakeholders, legal people to pay, and so on.
Also it says the Benedeks bought another German company after they sold their own company. So I guess that cost them a few million, too.
Your point is still valid - these people handed over substantial sums, between $10MM and $20MM each to a custom investment house.
What amazes me is...where they thought the money was coming from, for the helicopters and private jets.
If a single client justifies a private jet... well, for a going business, the money for the jet (whether chartered or owned) is coming out of that single client. $40k is 0.4% of $10MM. That's a pretty high cost for one meeting.
If the company treats all of its clients this way - each client has to pay that 0.4%. If the company treats only one its clients this way, or only a few of its clients this way, then it's a shady company. Either way, it smells, and it seems obvious from a distance. It's true that the article is the source of the $40k number for the jet, but fees for private jets (chartered or not) are not hard to estimate. Just read the economist, you can see the $$ in the ads.
I don't have $10MM to invest, but the unsustainable overhead seems obvious to me. It would be reckless to ignore it.
If the investment is $1B... a private jet seems required. $40k against that is tiny. I would EXPECT a private jet if I were investing a billion dollars. But for $10MM?