Check the thickness of the paper spacer. Realizing that it gets swept away on the first rotation of the flex plate, that would tell us that the actual gap is less than the paper spacer thickness. Since the flexplate can not be 100% true (i.e. a perfect diameter over 360 degrees), the spacer is likely there to help prevent contact between the widest part of the plate and the bottom of the sensor. Any contact, of course, would make noise and possibly damage the sensor. It is my understanding that too close a gap is only a concern for contact with the plate, but too wide a gap will reduce the Hall-Effect pulse and potentially cause missed pulses, missfiring, and error codes.