Ad Age just uncovered a Mexican ad agency secret that Donald Trump and his corporate friends might try to keep out of the U.S.A. "Mexico's Trade Group Follows the Money with New Model to Get Paid" headlines a recent article in that magazine. What is the new model? Mexican ad agencies are calculating and negotiating fees based on the amount of content they produce for each client -- with fees to be based on Scope of Work size rather than on arbitrary cost benchmarks dictated by clients. The effort is being led by the industry's trade association, AMAP (they're like the 4As, only more proactive) and Dentsu Mexican agency Flock, which was the first agency to embrace the concept. Since Scopes of Work are growing, AMAP and Flock reasoned, agency fees should grow as well. They've put the concept into action in Mexico.