Avoiding Fertilizer Application Less Sustainable?

We were recently denied a point on a project in which we worked with the landscape vendor to use half as much fertilizer as they were previously using. The reviewers said: "The narrative indicates that only a reduction in fertilizer use has been achieved. While reduction in the number of fertilizer applications is commendable, no environmentally preferable fertilizers were used during the performance period." This seems odd considering the goal of the credit is to minimize the use of chemical fertilizers. Using no fertilizer certainly meets this goal and is more sustainable than using fertilizer, even if that fertilizer is less environmentally harmful than a conventional one. In the future should we really focus on using environmentally preferable fertilizers instead of working with landscape vendors to avoid using fertilizer all together?