Well, they hadn't played When Love Comes To Town since 1992, and they pulled it out after a day of rehearsing it, no?
I think Two Hearts is a harder song to play (Edge has said it's his least favourite song due to the difficulty of the guitar part, and they would have to figure out the right key to play it in) but if it's something they want to do, they can pull it off.
For anyone curious, here's the Lovetown version of Two Hearts.
https://www.youtube.com/watch?v=aGpDxNITXAU
It was already played a half step down from the album version in 1989, so who knows what key they'd put it in now.