Musannaf Ibn Abi Shayba 13:1257

Abu Bakr narrated to us, he said: Ibn Abi Ghuniyah narrated to us, from his father, from al-Hakam, that he used to see no harm in a man having dinars owed to him by another man, so he takes dirhams from him, exchanging them. And he used to see no harm in him increasing the price for him or decreasing it, if it was by mutual consent between them.