REQUIRED: $4\mathrm{.}1$ Using the traditional method of overhead absorption based on machine hours, calculate the cost per unit for each of the three models of the product. $4\mathrm{.}2$ Calculate the cost per unit for each product model using Activity$-$Based Costing $($ABC$)$ principles, rounding off answers to two decimal places. $4\mathrm{.}3$ Explain why the unit costs of the three models of the product calculated under ABC differ significantly from those calculated using traditional costing methods. Use the results obtained in questions $4\mathrm{.}1$ and $4\mathrm{.}2$ to illustrate your explanation