my understanding is that it has something to do with the province's debt/credit ratings. paying it out all at once in the trough of the last recession hit them pretty badly. of course, that's selective accounting. they could just as easily look at the decrease in corporate taxes and blame it on that. but, it was instead decided that it wasn't structurally sound to make a habit of paying out that kind of sum on a yearly basis, and the process was changed to pay it out monthly or wait until the following fiscal year.

so, where's the interest on the money? well, if the state is holding it, it should pay interest, should it not? but, in a way, that's exactly the point.