It happened to me, check this thread:
http://www.canadavisa.com/canada-immigration-discussion-board/got-ita-but-completing-1-year-cec-experience-in-8-days-t318122.30.html/url]
I got ITA in July but my work experience anniversary is in August. You'll see in that thread that different members that different opinions on what i should do. I decided to wait until my anniversary date to submit, so that on the day i submit my application i could justify the points. I have submitted my application in September and had no issues so far.
Based on other threads, it seems that CIC gives you the points on the 1st of the month prior to the month which you completely an work experience anniversary. Since you have 60 days after the ITA to submit your application, so even if you receive an ITA today (oct 1) you can still submit your application after you complete that additional year of work experience in November.