Most payroll programs require a unit and a rate to give total pay.
A common payroll provider is 'Payline', and they normally calculate your fortnightly pay based on rate per hour.
i.e 80 X 24 = 1920 or 90 x 21.33=1920
As long as you are receiving the minimum of the award or certified workplace agreement (which is denoted as an annual figure) your boss is doing the right thing. If he/ she is underpaying then that's another issue.