Revenue estimates are sometimes at the mercy of the administrative process. If I'm developing estimates of corporate income tax collections for a state and I review the historical data and find that a large, but quantitatively imprecise amount of collections was moved from one fiscal year to another because overlapping vacation schedules caused the processing system to shut down in the last two weeks of a recent fiscal year, how should I consider tackling this problem in preparing my estimate - both in in terms of perfecting the historical data and in delivering my estimate?