I have created a segmented bend tube in sheet metal. The tube is a constant diameter. When I flatten the individual segments of the tube some of the flat patterns produced are incorrect for the circumference of the tube. In the attached file the first 6 segments produce circumferential lengths that are not correct by 200mm to 300mm. The last 2 segments, tube-12 & tube-13 are correct. I have tried adjusting settings but nothing fixes it. K factor is set to 0.5 but changing this will only make minute differences.