If you totally want to avoid flight changes, why not apply for entry visa to be on the safe side? Vancouver OCI processing has slowed down a bit and who knows what happens by end of the month. Those who follow Vancouver timeline closely may have more to say.Hope to get it. The ticket is super expensive without any refunds. I contacted Vancouver Consulate and no response for few days and then i received a reply saying 'there is no way to make OCI applications faster'. So you will have to wait. This was back on Oct 20th.