You can select 'before tax' on the Stats Can page you linked to, and see that the City of Waterloo is using the low-income cut-off (before tax) for a CMA of 100,000 to 500,000.
When were 2016 census numbers available? You're right that that's when we surpassed 500,000- maybe when the City last set rates for that recreation fee discount program, the 2016 population figures weren't yet available.
Edit: Where would GRT's $18,4xx come from, then? That doesn't align with any of Stat Can's cut-offs, unless maybe 2018 is available somewhere.
When were 2016 census numbers available? You're right that that's when we surpassed 500,000- maybe when the City last set rates for that recreation fee discount program, the 2016 population figures weren't yet available.
Edit: Where would GRT's $18,4xx come from, then? That doesn't align with any of Stat Can's cut-offs, unless maybe 2018 is available somewhere.