Not late until May? You have to be kidding...the cycle is already in the middle innings in terms of interview invites. Yes, there will be more interview invites to come, depending on the school, but to tell people they have a 'good 7 months' before it is late suggests that there is still time to apply and get secondaries done.
Some schools have already given out 75 percent of all the interview invitations they will offer; at the more selective schools, they will be filling remaining slots with late arriving superstar applications; if you were complete in August and have anything less than the most stellar stats, etc., you have probably already been passed over (edit: passed over at the top schools). Many schools will be completely out of interview slots in the next 60 to 90 days. There will be exceptions, but not many. By February, most schools will signal the obvious, that there are no more interview slots available.
On a related note: a few years ago, there was a Pritzker podcast that fleshed out one's chances at an interview invite depending on when applicants were complete; the contrast between the odds for a midsummer applicant vs the same applicant who was complete nearer to the official deadline was staggering - go find it. The take home message: Interview invitations are done on a first come, first served basis at most schools.
