The machine simply sews. It doesn't know if your seam is 1/4 " or not. You will probably benefit from a quilter's foot which gives you a quarter inch seam or maybe there is a mark on your soleplate that is exactly 1/4 " from the needle. Perhaps you can move the needle to the left or right to get an exact seam. Try some of the suggestions from this board and see if you can't get a better result. It's very expensive to trade machines if you don't need to do it.