The $2 billion was assumed to be sufficient whether in a recession or a slowdown, in the event that it ever were to happen. It's important to keep in mind that should the reserve not be sufficient, the government stands behind this and would cover any shortfall that would be needed to pay the benefits. So transferring an additional amount of money was not deemed necessary at this point, given the new rate-setting mechanism that will be put in place.
There were different figures mentioned a couple of years ago, but these were assuming keeping the rate stable throughout the economic cycle, which is not the case now.