If you take the payout over a certain time period instead of all at once, you get the additional amount that accrues over that time.

If you take the one-time payout all at once, you get the amount that would have to be there for it to have accrued to the full amount over time.

So in this case, there would have to be $290.6 million in an account for it to accrue to $643 million over whatever time period.

So you can either take the $290.6 million now, or let it accrue as you take it in installments, in which case you'll eventually get the full $643 million.

I think that's how it works.