1.work history section is included in EE profile for the sole purpose of assigning points for work exp. and hence no need to list out every job there...if you do,you will have to produce proof and CIC will check with each employer and will take two more months to process ur file..
2.Work exp outside Canada points are 50 for 3+ years...and that's it...so if you have any one job in primary NOC with 3+ years of permanent employment,that is enough... mention that only...(however go to come to Canada eligibility tool and see if your eligibility goes if you reduce ur work exp...u need 67 points
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http://www.cic.gc.ca/english/immigrate/skilled/apply-factors.asp )
3. only last 10 yrs details will get counted also...so leave out anything prior to June 2007..
4.you are required to furnish all the employment details in personal history while filing eAPR...but good thing is that they don't ask for any proof for those as you haven't claimed points..
5.Your three years of experience could be among multiple NOCs and even could be from different categories 0,A or B. You need to have at least one year in primary NOC....that's it...