PatMiere
There is no reliable answer to your question at this time.
Here is the problem as I see it.
1. At the release of the news version, Adobe has in the past announced free switch over from prior to new version within a defined grace period. But, I recall that being only when the purchases are from Adobe direct. Not sure if that would still be the case now.
2. If you purchase from Amazon (even if Amazon is labeled officially as authorized reseller), I suspect that you will have to inquire directly with Amazon about its exchange policies.
Since your planned purchase is from Amazon, why not give its Customer Service a telephone call to inquire about its exchange policies as it relates to your situation?
ATR