The Personal IAS is measuring two closely spaced lines as one line. What is going on and can it measure the lines separately?
With extremely close lines, the Personal IAS might interpret the space between the two lines as a light area in the center of one line. There are a couple ways to force the software to see the space between the lines as a line boundary: 1) Draw an ROI that only includes one line. This will make the software analyze the one line in the ROI. 2) In a full size ROI, position the unit so that only one lines edges are visible. By hiding the edge of one of the lines, it will be excluded from analysis.