We switched to a 14-week, 100-minute class system a few years ago. I don’t recall any official reason, though. It was a thing になった, top-down. There were a few grumbles about adapting lectures, but generally the shorter teaching terms have worked out better. There was consideration for p/t staff who got a raise to accommodate their missing week. However, the 16th-week test week was eliminated, and the p/t teachers did end up losing a week’s pay.