Ipill Effectiveness

Patient: Hi,I am married and has a kid of age 2. I had my last meriod on 8th March 2012.I had an intercourse with my husband on 19th March evening . Since got a small doubt on getting pregnant i took iPill. But it was taken at around the 74th hour. But in the note along with the pill it is suggested to have it within 72 hours. Please advice whether the Ipill taken 2 hours late than the recommended time of 72 hours would be effective to prevent the pregnancy if at all anything happened?