You should average those parameters over several SPOs to find out what the mean and standard deviation are. The last SPO may not have been average for accretion and discount.
You should also not use 4 significant figures where 1 will do, but to know that you would have had to realize the standard deviation of that number is likely to be at least as big as the other three significant figures.
We're in pretty good shape to get a SPO. I just don't think it takes mathematical precision of that sort to justify predicting it. Demand is there, and there's room to profit. That's enough.
I keep wondering why people think there's a trigger.
It's up to whether they need the cash, and can make more than book on the SPO shares. And whether they want to do it before and after the div. Or some other event. Or whether the moon is full of eels.
They're letting it run now because, as management said in the report and call, the MBS business looks lousy right now and having the cash won't help. Waiting for better spreads is their goal for the moment. The stock just goes up on its own due to the shiny, candy-like dividend yield.