Hi, may I kindly ask a question on a contractual claim. In the problem set of a moot, all questions and arguments were about breach of an implied term

Hi, may I kindly ask a question on a contractual claim. In the problem set of a moot, all questions and arguments were about breach of an implied term (an article of CISG on Actual Knowledge and Gross Negligence). However, in the contract in consideration, there is a similar express term with Best Knowledge qualifier in the warranties section (i.e. Actual Knowledge and Gross Negligence). As express terms generally take precedence over implied terms and there is no contradiction in this case, I am just wondering why the competition doesn't require students to discuss about the breach of the express term, which is a better argument? Thanks very much.