Musannaf Ibn Abi Shaybah 10207 — The increase above the prescribed due

Al-Hakam said: The Prophet (peace and blessings be upon him) sent Sayyiduna Mu'adh (may Allah be pleased with him) to Yemen and ordered him to take, on thirty cows, one tabi' or tabi'ah, and on forty, one musinnah. The people asked: "What is due on the excess between thirty and forty?" He refrained from collecting anything on it until he asked the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Do not collect anything on this excess."