(1) Allowable deductions from income include those required by law, those required as a condition of employment, and those necessary for the production of income. Allowable deductions may include:

(a) the amount of alimony or spousal maintenance which a parent is required to pay under a court or administrative order;

(b) for an "other child" as defined in ARM 37.62.103(9):

(i) the amount of child support due under existing court or administrative support orders; and

(ii) an amount equal to one-half of the primary child support allowance as found in ARM 37.62.121 for the number of other children for whom no support order exists and who:

(A) reside with the parent of the calculation; or

(B) do not reside with a parent of the calculation if a showing of ongoing support is made;

(c) the amount of any health insurance premium which either parent is required to pay under a court or administrative order for a child not of this calculation;

(d) the actual income tax liability based on tax returns. If no other information is available, use the federal and state income tax tables which show the amount of withholding for a single person with one exemption;

(e) the actual social security (FICA plus Medicare) paid;

(f) court ordered payments except as excluded under ARM 37.62.111;

(g) actual unreimbursed expenses incurred as a condition of employment such as uniforms, tools, safety equipment, union dues, license fees, business use of personal vehicle and other occupational and business expenses;

(h) actual mandatory contributions toward internal revenue service (IRS) approved retirement and deferred compensation plans. Mandatory contributions are fully deductible;

(i) one-half the amount of a parent's unreimbursed payments for an "other child" for extraordinary medical expenses and child care expenses necessary to allow the parent to work, less federal tax credits;

(j) extraordinary medical expenses incurred by a parent to maintain that parent's health or earning capacity which are not reimbursed by insurance, employer, or other entity;

(k) cost of tuition, books, and mandatory student fees for a parent who is a student as anticipated under ARM 37.62.106(5); and

(l) the current, annual interest on student loans, paid by a parent of the calculation for post-secondary education that has resulted in an economic benefit for the children of the calculation.

(2) Allowable deductions from income for child support differ from allowable deductions for tax purposes.