I just went with what I saw on the website..if and unless my English isn't that great .. it states that PGWP can be extended with exceptions....
"Applying for a work permit
If you have not worked in Canada in the last four years, you can apply to work in Canada for a maximum of four years. You should keep track of the time you work in Canada, up to a maximum of four years.
If you have worked in Canada in the last four years, you will be allowed to receive a work permit for a period of time that adds up to – but does not exceed – the maximum of four years of work in Canada. All work you do in Canada counts toward your four-year maximum, including all:
Jobs in the National Occupational Classification (NOC)
Jobs that require a labour market impact assessment (LMIA) and jobs that are LMIA-exempt
Jobs with open work permits, including the Post-Graduation Work Permit
Jobs that are exempt from work permits
Work completed during implied status
Internships (if they are not part of full-time studies)
Unpaid work
Work as a volunteer
Self-employed work
Exceptions
When you work within one of the occupations or categories listed below, the time you work in Canada is still counted toward your four-year maximum.
It is only when you apply for a work permit that these exceptions become relevant. An officer may issue a work permit to you if you have a job offer in one of these occupations/categories, even if you have already worked in Canada for four years.
These categories or occupations are the exceptions for which a work permit can exceed the four-year limit:
NOC O and A (including spouses/dependants of these skilled temporary foreign workers)
LMIA-exempt jobs under
International agreements
Canadian interests
Self-support
Humanitarian reasons
Jobs that do not need a work permit
Permanent resident applicants who have received a positive selection decision or approval in principle
Provincial nominees applying for an employer-specific work permit
Any work done while studying in Canada on a full-time basis does not count towards your four-year maximum.
Gaps in employment
During the time that your work permit is valid, you should keep track of any periods of one month or more when you do not work. These gaps in employment may be considered in the calculation of your four-year maximum, as long as you provide proof of these gaps when you apply for your next work permit.
Some examples of acceptable gaps in employment are:
Periods of time spent outside of Canada
Periods of medical leave spent in Canada, if this period is not covered by the employment contract/agreement
Periods of unemployment in Canada
Maternity/parental leave spent in Canada
Some examples of proof documents are:
Passport entry and exit stamps
Official documents indicating that the job started and/or ended on certain dates; for example, a Record of Employment or proof of receipt of severance pay
Letter from a foreign educational institution stating that you were attending their institution for a period of time during the work permit authorization;
Travel receipts, including tickets and boarding passes showing that you were out of the country for a period of time during the work permit authorization, other than a period of paid leave (e.g. sick leave, vacation leave) from your job
Proof of receipt of maternity/parental benefits
Letter from a doctor confirming you were on medical leave for a certain period of time"
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