•   A parent's taxable income is generally the amount of taxable income that is assessed under an Income Tax Assessment Act.

•   The Registrar may determine a parent's adjusted taxable income in certain circumstances.

•   There are limits on the Registrar's ability to amend an assessment for past periods if the parent later lodges his or her tax return.

•   A parent can estimate the amount of his or her adjusted taxable income for a year of income.