I hope that's right. Because Kuro should really pay for his own wish.
I agree- Kurogane has to pay for his own wish.
Here's what I figure for the rundown of the wish situation, since it's confusing:
1- Kurogane wanted to save Fai's life. Subaru wanted water for the reservoir.
2- Yuuko says that it would be too expensive for Kurogane to wish to save Fai's life.
3- Yuuko then has Kurogane wish for the water.
4- Yuuko then tells Subaru to give his blood to Fai (for Kurogane's sake) to pay Kurogane for making Subaru's wish for him.
5- Kamui refuses to let Subaru give Fai his blood, and instead gives his own blood to Fai. Therefore, Subaru does not have to pay any price for the wish that was originally his. (Will Subaru then be in debt to Kamui?)
So Kurogane still owes for the water, since the water has been delivered. Unless Sakura is paying for the water, which doesn't make any sense.