I'd caution you on upgrading, or at least paying very much to do so. D&D books aren't a high-priority "new release" and they aren't going to spend any time trying to time the shipment to arrive on the 6th. They may not even worry about getting it out the door on the 6th.
I stuck with the free shipping because I don't expect to get the books until the next week, anyway, and I figure what's the difference between seven and nine days, really? If it was actually going to shave off a week, I might rethink.
YMMV.