I read it as you can cancel your passe and get a refund from the day the parks closed till the day of your expiration. Once you call to cancel though you are done, you do not have a pass any more. The one month is just a little something to keep people from canceling, although it's not much. I may be wrong in this though. Maybe they are allowing a refund for just the closed days, but if you take that refund you do not get the extra month. IDK
We are just going to keep ours with the four month plus one month extension. Ours were going to expire in June anyway so we would have only gotten a three month partial refund. We are going in July, and now with this one month extension I may take just the kids for a long weekend in November right before our passes expire since their grandparents will be there at that time anyway.