"That would be someone else to target, or a later one. The deal I want is pointed at the Hallows."

Because they did not work right. They did not seem right. Why would they need a human soul to burn now? They worked before, sealing him away and sending the human through time a couple times. Or maybe they didn't have the understanding of them? No matter, he wanted them working like they should which should also free Zhao Yunlan in the proc4ess.