The advantage of this system is that it allows you to compensate for problem areas. Even if you have a low GMAT score, evidence of a high GPA, quantitative work experience, or the completion of an accounting or statistics course will provide a strong counter-balance.
No one single thing counts more than everything else. Your scores, work experience, and essays should give the admissions committee a clear idea of your capabilities, interests, and accomplishments. Any particular weakness can be overcome by a particular strength in another area, so make sure you emphasize whatever strengths you have and don't take them for granted.
