[Compromising Cash for a Deferred Debt]

Answer—and Allah is the granter of success: The scholars of the madhhab have forbidden that, as in al-Azhar. Al-Mu’ayyad Billāh (Peace Be Upon Him), however, said it is sound and permissible. The reasoning—as in the marginalia—is that it amounts to remitting part of the debt and deferring part of it. Imām Sharaf al-Dīn upheld this.
I say: This is preferable, due to Allah, Exalted is he, saying: “And if someone is in hardship, then [let there be] postponement until [a time of] ease; and if you remit it as charity, it is better for you.” [Al-Baqarah:280]. The verse urges both postponement and remission—when the two are of the same kind. As for when they differ—such as settling with gold in place of silver—that is not permissible. Whoever remits part and grants delay on the remainder has done well. Their statement that it is like selling ten for five is unclear. Consider this—and Allah knows best.
Source: Min Thimār al-ʿIlm wa al-Ḥikmah vol.2