Schiffer corporation manufactures agricultural machinery. at a recent staff meeting, the following direct-labor variance report for the year just ended was presented by the controller. schiffer corporation direct-labor variance report direct-labor rate variance direct-labor efficiency variance amount standard cost, % amount standard cost, % january $ 800 f 0.16 % $ 5,000 u 1.00 % february 4,900 f 0.98 % 7,500 u 1.50 % march 100 u 0.02 % 9,700 u 1.94 % april 2,000 u 0.40 % 12,800 u 2.56 % may 3,800 f 0.76 % 20,100 u 4.02 % june 3,900 f 0.78 % 17,000 u 3.40 % july 4,200 f 0.84 % 28,500 u 5.70 % august 5,100 f 1.02 % 38,000 u 7.60 % september 4,800 f 0.96 % 37,000 u 7.40 % october 5,700 f 1.14 % 42,000 u 8.40 % november 4,200 f 0.84 % 60,000 u 12.00 % december 4,300 f 0.86 % 52,000 u 10.40 % schiffer’s controller uses the following rule of thumb: investigate all variances equal to or greater than $30,000, which is 6 percent of standard cost.