A mechanical planimeter is used to trace the boundary of a tract of land drawn to a scale of 1 in = 100 ft. It is calibrated so that 1 unit on the planimeter scale equals 0.025 in2 of area. When the tracer point is positioned over the starting point on the perimeter, the initial reading is 3456 units. After tracing the perimeter once, the reading is 4970; the final reading after tracing the figure four times is 9536. What is the scaled area of the tract, in acres?