Deductions from monthly gross income must be allowed as follows:
(1) Income taxes payable based on the applicable tax rate for a single taxpayer and a monthly payroll period rather than the actual tax rate;
(2) Social security and Medicare taxes based on the applicable tax rate for an employee or a self-employed taxpayer;
(3) Contributions to an IRS qualified retirement plan not exceeding ten percent of gross income;
(4) Actual business expenses of an employee, incurred for the benefit of his employer, not reimbursed;
(5) Payments made on other support and maintenance orders.