Under the tax collection agreement signed between the provinces and the federal government, those provinces that did keep their corporate tax administration--Ontario, for example--manage their own, but for all the other ones, where we have tax collection agreements, especially on individuals because that's the most widespread one, the provinces are paid on the face value of the assessment. Penalties, interest, and costs of writeoff are actually absorbed by the federal Crown. So there is a process by which, every year, that cycle ends, and that sets the reconciliation of how much money will go on a monthly basis or be retroactively adjusted.
On June 6th, 2006. See this statement in context.