What is the secret behind the mention of the word "istawā" (ascended/established) in the story of Musa (peace be upon him) and its absence in the story of Yusuf (peace be upon him), despite the similarity of the two verses?

Ibn Ashour said in "Al-Tahrir wa Al-Tanwir" that "al-ashadd" (full strength) is the perfection of power, and "al-istiwaa'" (maturity/steadiness) is the perfection of physique. This is why "al-istiwaa'" was mentioned for Moses but not for Joseph; because Moses was a tall man, complete in his physical build. This is supported by what was narrated from Mujahid, Ibn Abbas, and Qatadah, that "al-ashadd" is thirty-three years, and "al-istiwaa'" is forty years.