Sandhill Corporation currently manufactures 4,400 staplers annually for its main product. The costs per stapler are as follows: Direct materials $3 Direct labor 7 Variable overhead 4 Fixed overhead Total 7 $21 Gallup Company has contacted Sandhill with an offer to sell it 4,400 staplers for $18 each. $5 of the fixed overhead per unit is unavoidable. Prepare an incremental analysis for the make-or-buy decision. (Enter negative amounts using either a negative sign preceding the number eg.-45 or parentheses e.g. (45).) Incremental savings on direct materials Incremental savings on direct labor Incremental savings on variable manufacturing overhead