I don't think you understand the game.
1BTC goes in, and exactly (almost) 0.98btc is given as dividends.
If you hold on to b.exch (b.sell+b.mine) you are guaranteed a 2% loss (or whatever the fees are)
To put it simply, B.exch = b.mine daily div x 200. B.sell dividends = excess btc when difficulty increases lowering the amount of btc required to pay 200 days worth of b.mine divs.
BTW as anyone who has been mining for more than a week knows spreadsheets and calculations are just about as accurate as palm readings and fortune cookies.
But if you don't believe me then I'd encourage you to read/fully understand the rules and play the game as there is huge money to be made by anyone who can predict the future.
So my 30-day analysis spreadsheet of B.EXCH is in error then? Is this FINALLY your point?
...and why would anyone buy and hold (for dear life) B.EXCH? (B.MINE+B.SELL) That's stupid. Do it for short terms at a profit. WATCH B.SELL's dividends (esp. lack thereof) like a hawk... it's a HOLD or EXIT signal.
With the buy back (even @ 2% less and especially so), you can't miss.
FYI what you dismiss as "predicting the future" I subsume as statistical analysis.
I just have a problem with Panamanian dictators. Wildcard.