Only count those stitches “above” the cable when casting on. Your actual number of stitches when knitting your Moebius will be double the number you cast on (216 stitches above and 216 below the cable).

Each half is a multiple of 16 sts plus 8 or a multiple of 16 sts when both halves are added together (432/16 = 27). The overall circumference may be adjusted by adding or subtracting multiples of 16 stitches. Each half must remain a multiple of 16 sts + 8 or the pattern will not work (ex.: 248, 232, 216, 200, 184, 168, etc.). The width is determined by the number of pattern repeats you do. Always end on pattern row 8 or 16 to fully complete the rectangles.