Windsor Inc. makes unfinished bookcases that it sells for $60. Production costs are $38 variable and $9 fixed. Because it has unused capacity, Windsor is considering finishing the bookcases and selling them for $70. Variable finishing costs are expected to be $7 per unit with no increase in fixed costs. Prepare an analysis on a per-unit basis that shows whether Windsor should sell unfinished or finished bookcases. (If an amount reduces the net income then enter with a negative sign preceding the number, e.g. 15,000 or parenthesis, e.g. (15,000). The bookcases processed further