Hi Pippin and alcat,
Though I'm not expert to answer this specific question, however, read below from the OB 120. So this means that if you do 80% then I assume you should be ok.
"For SW1 (one of the 38 occupations listed in the MI), review the documents related to work experience. These documents should include those listed in the Appendix A document checklist of the visa office specific forms. They should include sufficient detail to support the claim of one year of continuous work experience or equivalent paid work experience in the occupation in the last 10 years. Documents lacking sufficient information about the employer or, containing only vague descriptions of duties and periods of employment, should be given less weight. Descriptions of duties taken verbatim from the NOC should be regarded as self-serving. Presented with such documents, visa officers may question whether they accurately describe an applicant’s experience. A document that lacks sufficient detail to permit eventual verification and a credible description of the applicant’s experience is unlikely to satisfy an officer of an applicant’s eligibility."
