Answer:
the sales level for year 4 was missing, so I looked for similar questions:
Sales level year 4 = $38,900
macrs depreciation:
period % amount
year 4 11.52% $32,000 x 0.1152 = $3,686.40
NCF year 4 = {[net sales x (1 - variable costs)] - depreciation - fixed costs} x (1 - tax rate) + depreciation
NCF year 4 = {[$38,900 x (1 - 67%)] - $3,686.40 - $12,600} x (1 - 34%) + $3,686.40 = $1,409.80