I don't see how this can be completely wrong. And I never stated that when you're HU in an SNG, the calculation would be different. My ICM remark was when there are more than 2 players. Then you can use ICM to determine your EV when you bust.
On the contrary, you say that with the correct calculation it is possible to lose more than a BI or to win more than the 1st prize. This is complete bollocks of course. Your Expected Result in a single tournament can NEVER be less than the buy-in or more than the 1st prize. The definition says it already itself, the Expected Result of your tournament, is what you would win 'on average'. How can the average be less than the minimum or more the maximum ???
I don't have a reference to this method. It's pure common sense.
Again let me give the example. Say we play a hyper HU SNG with 500 chips each. 1st prize is $10.
H1: I win a showdown hand for 250 chips. I'm now leading 750-250.
H2: We have a preflop all-in coinflip. I'm now 50% favorite to win the $10. So from the $10 I'm entitled to $5 already. There is a 50% possibility we'll have to keep on playing for the other $5 equity. I do lose and we're back at 250 each.
H3: I again win a showndown hand for 250 chips and leading 750-250
H3: We again have a preflop all-in coinflip. I'm again 50% favorite to win. Of course I win $10 when I do, but the tournament could have ended in H2 already and EV wise there is only $5 to distribute anymore, so I'm entitled to 50% of that $5 instead, i.e. $2.5. I however lose and we continue playing for the remaining $2.5 equity, with 500 chips each again.
H4: We have a preflop all-in coinflip. I'm 50% to win the tournament for that remaining $2.5 equity, opponent has the other 50%.
So the total $EV for me in this tournament is $8.75, and for my opponent it's $1.25.
You could calculate it differently as well. My opponent needs to win 3 consecutive coinflips to win the tournament. If he had lost any of the coinflips, he would have lost the tournament. So he had a .5*.5*.5 = .125 probability of winning the $10 and a .875 probability for losing, which also leads to an $EV for him of $1.25.
If I understand correctly, the new method will simply add the cEV of every individual hand. If you do that, you will end up with a cEV=1250, meaning a $EV of $12.50.
EDIT: and I'm definitely going to read that 2+2 thread as soon as I have time, because I cannot imagine that not a single person would have posted something like that.