Quick tongue tie assessment questions re norms, lateral scale

Are there average norms to use when you work with the ROM QTT scale?  I believe that there would not be a difference regardless of age but there are no norms as of this time.  Remember that it is used as a “quick” screening assessment tool for tongue tie, not a detailed assessment.  It is more of a “red flag” that indicates you should look more deeply into the possibility of a restricted lingual frenum.  How am I supposed to position the ROM scale?  The ROM notch is placed upon one of the lower central incisors while the patient makes the moves of opening mouth comfortably (or suctioning or TTS) and you keep the notch on the lower incisor and roll the ROM gently upward as an arc, to see what the measurement is when you touch the matching upper central incisor.