If your application has already been scored with high enough points to get you an interview, and as the website states that the highest MCAT is the one they judge by, and because the interview is blinded, then individual adcomm bias will not come into play due to seeing a lower MCAT score. Consider yourself to be on a level playing field as you prepare for the campus visit. It's for you to add to the "points" the admissions committee will see when they take the final vote on your status by having an exemplary interview.
Check the Interview Feedback section of SDN to look for likely questions for that campus. Practice, practice, practice. Be confident. Don't mention the second score.