The link you have cited is for work permit, not pgp. Looks like its a different requirement for different streams. For
express entry, its 10 years. I haven't found anything specific for pgp.
please read it again (Bold and underline font )
In most cases, you’ll need to get
police certificates for countries or territories where you’ve spent 6 or more months in a row since the age of 18.
General information:
Police certificates
In most cases, you’ll need to get
police certificates for countries or territories where you’ve spent 6 or more months in a row since the age of 18.
When processing your application, an officer might ask you for more police certificates.
How long is my police certificate good for?
For the country or territory where you currently live, the certificate cannot be older than 6 months from the day you apply.
For any other country or territory where you’ve stayed for 6 or more months in a row, the certificate must have been issued after you left. You can use the certificate for your IEC application as long as you haven’t gone back to that country or territory.
Uploading your police certificates
There will only be
1 upload field for police certificates. If you need to give us more than 1 certificate, make sure to include all your certificates together in 1 single file.