Originally Posted by
mctaste
doesnt seem too ridiculous for a cash upgrade to D1.
One-way???
That said, the current r/t fare for Feb 2, returning a week later on the nonstop is $10,347. Half that is $5,174 which is $332 more than the OPs upgrade offer, and it's conceivable the OP is on a ~$700 r/t coach ticket.
So the buy-up price makes sense in the context of the current fares, but that doesn't mean it's not ridiculous! (Especially since usually upgrade offers are not usually dynamically based on pure fare differentials IME.)