An eligible educator who files a return of income for a taxation year and who makes a claim under this subsection is deemed to have paid, at the end of the year, on account of tax payable under this Part for the year, an amount equal to the amount determined by the formula A × B where A is the appropriate percentage for the year; and B is the least of$1,000, the total of all amounts each of which is an eligible supplies expense of the eligible educator for the year, and if the eligible educator fails to provide the certificate referred to in subsection (3) in respect of the year, as and when requested by the Minister, nil.