I'll duplicate to you again what I asked. One positive response and one negative. Ascended Astarion has a positive answer in the first dialogue, "I just wanted you to be happy." There is nothing terrible if there is a similar option in the second dialog.
I read through the entire dialogue tree for this conversation, and where would a second neutral option lead? How could the dialogue tree and later scenes look like?
From a more literature major point of view, the lines "But make no mistake, I will forever remember what you did for me today. And one wicked turn deserves another. So, tell me what you desire. What can I do for my dearest pet?" are probably meant to set up a new frame of mind for Astarion and the player, while mirroring the "This is a gift you know, I won't forget it" from act one. Both are huge moments for his arc, one framed as a gift, another as a transaction.
