Magnanimous Prosecutor wrote:
It's only 75% for the first $100-$200.

Not quite.

Contribution Tax credit
$0.01 to $400.00 75 percent
$400.01 to $750.00 $300 plus 50 percent for contributions over $400
$750.01 to $1,275.00 $475 plus 33⅓ percent for contributions over $750
$1,275.01 and over A maximum of $650