Having gone through this myself, let me clarify something. Once you void the test it is considered that you have taken the test according to MCAT but it is not reported to AMCAS. So there is a distinction. In other words, MCAT knows you have taken the test so that when you take the test 3 or more times, they can request your intent to apply to medical school. However, for AMCAS purposes it is never reported.
Right from the MCAT booklet:
If you void your answer documents, your participation in this administration will not be reported to AMCAS or to non-AMCAS schools. However, even if you void, you are regarded as having attended the test for test administration purposes, and, therefore, you are not eligible for a refund. Also, if you wish to register after having attended three or more MCATs (whether you voided your scores or not), you must request and obtain permission each time you wish to retest."