Another question... Sorry for bombarding this thread today

I'm just super excited (and 1st time applicant)!
What is used to determine who gets an interview? Is it 100% based on your GPA from the 4 most recent terms? On the application form it says that academic honours, work exp, extra curricular, volunteer are not used in the selection for interviews.
Then for determining the final rank order for those that are offered admission after interviews it says they use "Average GPA of last 4 full-time undergraduate terms: 30%, MMI performance: 45%, Essay performance: 20%, References: 5%". When do they actually look at work, volunteer, extra curricular etc?