I will add to the budget topic, since it's a very valid consideration and several people have mentioned it. If the $700 would be handy on anything else at all on the trip, then it's probably not in your budget. If spending it to stay at BC doesn't cause you to blink an eye or change your plans, then it sounds like it probably is. Only you can really make that call.
We budget our categories ahead of time, so moving to a more expensive resort, or adding another TS ADR is really about what do we have budgeted already for that category, and they don't overlap. If we have $1000 left in the Resort category, adding another day or two, or upgrading is on the table. If we have $20 left in Dining, adding a V&A night might not be in the cards. But, budgeting for many people is like making biscuits in the South. Everyone generally has a method they like best, and you never want to suggest that your way might be better.