The amount of payments in lieu of constructing affordable units on site shall be based on the cost of constructing each new residential unit, less proceeds anticipated from the sale of the unit or the capitalization of rental income from the unit. The cost of constructing new residential units includes the sum of development hard costs, related soft costs and developer's fees pursuant to the cost containment provisions of N.J.A.C. 5:43-2.4(a)1 through 6, and land costs equal to 25% of the first quartile of new construction costs as reported to the Homeowner Warranty Program.