Multi-day Ticket Purchasing Question

We are planning a trip for Dec. 14-20, and will be purchasing 6-day park Hopper tickets. I noticed using the ticket calculator that the tickets are cheaper if you purchase them listing December 12th as our first day in the park rather than the 14th. Is there any problem with purchasing the tickets this way (i.e., listing December 12th as our first day when we will not be arriving until the 14th)?

There was some debate on this when Disney first announced the date-based ticket pricing.

The idea of picking an earlier date to get a lower ticket price seems reasonable, but there was some speculation that if you show up two days (or whatever) later than your actual purchase date:

  1. Disney may in fact charge you the revised price when you arrive, or…
  2. Allow it as long as you finish using your tickets in the day window.

In the second case, if you are buying 6 days, you get, I believe 9 days. This means that if you buy them starting Dec. 12, but don’t start going until Dec. 14, then you effectively use up 2 of those 9 days, leaving you 7 days to use up your 6 day tickets.

I’m not sure if anyone has tried to confirm what their actual practice is.

ETA: I should add that most likely it is option 2, based on the following wording on Disney’s own site:

“For example, a 6-day base ticket with a start date of November 1 is valid any 6 days from November 1 to November 9.”