Difference?

The Rambam famously states that the mitzvah of the shofar on Rosh Hashana isn't the blowing of the shofar, rather to hear the shofar blown. He puts forth this understanding in Sefer Hamitzvot #170 and codifies this understanding in his Mishne Torah in the Laws of Shofar at the beginning and in Ch. 2 Law 1. He describes this in greater detail in his Teshuvot Pear Hador #51. However, when it comes to the Laws of Yovel (10:10) and in Sefer Hamitzvot #137 he says the mitzvah to blow shofar on yovel is a mitzvah on every individual to sound the shofar. Where does the Rambam get this difference from?