Dear Pitabisit,
As per my understanding, CIC update (complete application received by CIC) represent total number of application opened for Assessing the application against Ministerial Instructions after Completeness check upon receipt. They do not count total received application for this update.
My above said understanding is based on my current and last year experience, here are the points which can justify my above understanding:
1. My complete file was delivered to CIO last year on 1st may 2012 and opened for Completeness check on 03 May 2013. Total overall Cap was reached on 08th may 2012, (second last update was on 28th April in which only 78 application was left towards overall Cap reach.) but the received letter explaining the Cap reached is of 21 May 2012 which means my file was opened for Assessing against Ministerial Instructions just before or on 21st May 2012.
2. And this year, many applicants (including some June- July applicants) got their file back just because their file was incomplete or incorrect and therefore couldn't crossed the Completeness check stage. And those who crossed the Completeness check are placed in the long queue for getting assess against Ministerial Instructions.
Now, for example Current updated for NOC 1112 is 278, that means there will only 22 more application out of long queue which will be proceed for Assessing the application against Ministerial Instructions rest would be return back due to cap reach.
In Short, Cap update don't represent total number of received application, it represent the number of application opened for Assessing the application against Ministerial Instructions (All these application get their PER/NER and get charged for processing).
This is just my view, experts please correct if it there is something wrong.
. I remembered that it was my first application that I sent to cic. I called again at the same number and told the agent that I need some information for my current application which was received by cic on may 31st, 2013. He took my information, checked in the system and told me that he cannot find any information for my application for this year and advised me to send cic an email and wait for their reply. 
