Where overpaying actually happens is on the buy side. The new, smaller home carries its own City of Saskatoon assessment and mill rate, and financing a purchase with mortgage insurance triggers Saskatchewan's PST on the premium at closing, on top of legal fees that typically run $800 to $1,500 through the lawyer who handles the title transfer.
Timing between the sale and the purchase matters too. A senior who buys before selling can end up carrying two sets of costs at once, while one who sells first without a confirmed next home risks a rushed purchase in a market with 1.63 months of supply.
Sequencing the sale, the financing and the possession dates correctly is where a downsizer actually loses or keeps money, more than any single tax line. Get your hand-reviewed valuation from Joel Dyck.