nope, no assumptions there. There is no such thing as you granted interview- you are shoe in. Even UOP that gave in the past 97% acceptance rate after interviews may or may not do it this year.
Overall there are 3 invites per one seat. Acceptances given 1.5-1.7-2 per seat depending on the school. Higher priced private schools will give slightly more acceptances as they know people will go the instate schools for cheaper tuition so turnover is more. So at least 1 out 3 is not receiving acceptance after interview.
Also remember schools do not have to wait till Dec 1 to send you rejection letter after interview.... some schools have done that in the past real fast...