I think that the point that confuses the instructors in this thread is that air consumption is not a skill which divers are tested on, and therefore cannot be the basis for failing or denying certification to a student. Although I agree with many of the posters that air consumption is important, I don't know of any agency in which it is legal to fail someone on air usage.
By the same token, passing the course cannot be based on whether or not the instructor feels the student is ready, if the student exhibits mastery of the skills set forth in the standards, the instructor is compelled to pass the student.
By the same token, passing the course cannot be based on whether or not the instructor feels the student is ready, if the student exhibits mastery of the skills set forth in the standards, the instructor is compelled to pass the student.