Annual salary amount on payslip

Hi.  I administer a payroll where all employees are paid at an hourly rate and their hours are different every fortnight.  On their payslips is an "Annual Salary" amount which is their hourly rate multiplied by "Hours in fortnightly pay period" which is a required field in the "wages" area of the Employee Card File.  This Annual Salary amount on the payslips cause me no end of troubles (staff want low annual salary, staff want high annual salary etc) and it is meaningless because their annual wage cannot be predicted with any certainty and is therefore not strictly a "salary".  Is there any way to get rid of this amount on the payslip altogether?  Thanks.