The flexibility that CWB staff have mentioned to us in discussing this section is the possibility of running a number of concurrent pools, which in aggregate might add up to more than a year. I think our reading of these words is that it would be allowed because what you're talking about is the definition of “pool period”.
As for the question of whether a multi-year pool is a greater risk for the initial payment guarantee than a shorter pool, that's something with which we don't have a lot of experience, so I'm not going to try to offer a factual answer to that.