Codes, in general, delineate the minimum requirements. The contractor/manufacturer/fabricator can institute more stringent requirements in their in-house procedures as long as those in-house procedures at least meet the minimum requirements of the codes invoked by legislation.
This holds true with many welding standards as well. The ASME sets out the minimum requirements for the information presented in a WPS, it specifies what data and tests must be performed when qualifying a WPS, but it does not prohibit a company from writing WPSs with more information for the welder nor does it restrict the company from performing additional tests as they see fit for their intended purpose.
I am not familiar with CWB requirements, but I suspect they follow the same lines of thought as US welding standards.
Best regards - Al