Gauge question

Hi, everyone. My gauge is a little bit off and I was trying to figure out how much this would affect the sweater size, which brought up another question. I'm making the 38/39 size. I CO 103 for the back and 50 for each front, totalling 203. Divide that by the required gauge of 4.75 spi and you get 42.74 inches. Why is it so big when the finished sweater is supposed to be 38/39? I know the bottom is ribbed and will draw in, but the plain panels won't. How is this supposed to be sweater with a finished measurement of 38 or 39 inches? Am I missing something? Thanks.