I can speak to it from Nova Scotia's perspective, and actually across those three jurisdictions I've worked in.
I'm a fan of consistent use. I think the tests set out in the laws tend to define either consistent or compatible, and those rules are helpful in allowing for secondary use in those limited circumstances. That gives the definition “incorporates necessity and proportionality” in some of those pieces of legislation. Certainly, trying to be as consistent as possible with secondary use across the two, PIPEDA and the Privacy Act, would be helpful.
I've applied the consistent-use test and found it really works well for secondary use.