“General Mazloum is willing to negotiate with you, and he is willing to make concessions that they would never have made in the past.”

这句话出自10月9日美国白宫给土耳其总统的一封信。句意不难理解，但是我不明白为什么第二句的从句会用过去将来完成时“they would never have made”，而不是“they have never made”。

语法资料上说过去将来完成时“表示从过去某一时间来看将来某时会已经完成的动作”，但我觉得这句话并不属于这种情况。为什么不写成“he is willing to make concessions that they have never made in the past”呢？

希望能得到解答，谢谢！