I don't have any specific knowledge of Hinson's contract, but the article did refer to the $128,500 figure being his "base salary". There are ways for a coach to make many times that amount even if the base is just $128K. Some coaches have contracts that allow income from summer camps, radio and TV gigs, shoe contracts, consulting deals, endorsements and commercials that is additional to their base salary.
Other college jobs include all that extra income in the contract amount, and prohibit the coach from other outside earnings unless they are arranged through the school. For as long as Barry has been at MSU, that figure sounds low, and I would suspect his contract is supplemented with some of that extra income.