Maimonides Minute – Hilchot Shofar 3:12-13 (Blowing shofar versus saying Musaf)

Why does the Rambam only require one set of shofar blasts after each of the berachot of Musaf, rather than three sets (as most Ashkenazic congregations do today)? If a person has a choice of spending Rosh Hashanah in a city without a shofar, but with a chazan, or in a city that may or may not have a shofar blower but does not have a chazan, which choice is halachically preferable?