BDD End-Game via Decrease
The second possibility is that Difficulty stagnates or decreases and the fund Reserve is deficient (no longer holds 200 days of dividends at current Difficulty). In this scenario, BDD.MINE (and BDD.EXCHANGE) will continue to receive daily dividends until the funds capital is exhausted. BDD.SELL would receive no further dividends and all shares would be bought back (forced) for no value (as all funds would have been paid out to BDD.MINE and BDD.EXCHANGE).
This section is should be clarified. I assume that it means that when the difficulty stagnates or decreases, MINE will continue to receive dividends and SELL will not, until the fund runs out of coins and closes. However, it could also be interpreted as: when the difficulty decreases (even just once), all SELL are bought back at 0 price and MINE continues to receive dividends (and live happily ever after).
Also, when I compute the daily dividends for MINE using the info from the Bitcoin wiki, I obtain a value that is 2 satoshis per day per share higher than what has been paid out to MINE. This discrepancy could be a rounding error, but those typically shouldn't exceed 1 unit at the smallest denomination. Could you specify which equation you use to compute MINE dividends?