So if you post 1 BTC on Team A to win and 1 BTC on Team B to lose.
Lets take tonights game for example Colts at Jags. Colts are a 3.5 point favorite. So you would bet Colts on the first site and Jags on the 2nd.
OK so you need to fix your OP. It should read:
So if you post 1 BTC on Team A to win and 1 BTC on Team B to
lose win.
So you are just betting both sides of the bet. Assuming there are no costs associated with placing the bets your expected value is exacly 1.0. In other words, you have eliminated the possibility of losing, but at the same time you have eliminated the possibility of winning anything also. You bet, one bet wins, you get back exactly what you bet. Might as well have not wasted you time betting right?
So this brings us to:
The ROI all depends upon the discounted money that is purchased.
So you are claiming that you have somehow figured out a way to use this discounted money to your advantage.
Let's look at you example now:
Here's the breakdown. Tell me, PLEASE TELL ME, how this is wrong:
Investment A - 150
Investment B - 127.50 (150 bought at .85)
Return on Investment - 300
Gain (total) - 22.50
Gain (per person) - 11.25 = ~1BTC
Not quite, there are
two possible outcomes for the bet
Total amount bet = 150 + 127.50 = 277.50
"Investment" A wins, total profit = 300 - 277.50 = 22.50 (yahoo!)
"Investment" B wins, total profit = 300 - 277.50 = 22.50, right?
But wait a minute! The $300 is now sitting at a site where you have to take a discount to get your money out (the premise of this system) so you don't really win the full 300. In fact once you claim the winnings on that site you only get 0.85 of 300 or $255, so the real take home from this second case is:
"Investment" B wins, total profit = 300*0.85 - 277.50 = 255 - 277.50 = -22.5, you lose 22.5 in this case!
So in the long run you will win 22.5 half the time and lose 22.5 the other half of the time giving us the expected value of 1.0 for betting both sides - the expected result.
BUT WAIT YOU SAY! I can just keep going until A wins, right?
No, after B wins you have $300 on site B but this money is already discounted money so if you bet with it in the next round there is no mathematical advantage.
In the long run the expected value of this system is 1.0, assuming no transaction costs.