I think @ MapleLeafCEC has a point.
It is legal to work full time while Off campus work permit (OCWP) is still valid, while to CIC s/he is still a student. However, on CEC application, one has to work, after graduation and under worker status, for 1 year. So if someone who counted his/her experiences under OCWP, he had included time where he was still considered not graduated and therefore not a student. Thus those time were not counted.