Is prolonging the prayer specific to the Prophet (peace be upon him), as was inferred from his Hadith to Mu'adh?

The Prophet's (peace be upon him) variation in the length of his recitation during prayer, between prolonging and shortening, was according to the circumstances of the congregants. He would prolong if he knew they preferred prolongation, and shorten if he knew otherwise. Similarly, jurists have explained that the Imam prolongs if he knows the congregants desire and are able to endure it.