As per canada.ca, the base credit for the GST credit is $580 for the 2018 base year. However, on ProFile, the base credit is only $290. Is this an error? How do I get ProFile to calculate the credit properly?
You can override the base amount(s) on the GST form in ProFile from $290 to $580 if you want this change to appear on the letter. The GST information is not submitted to CRA since CRA makes their own calculation, so, even without this override, CRA will make the calculations based on updated information on their system