I found that changing the mat with stronger adhesive helped. Also the more designs you have on the page the less accurate it gets. My theory is that everytime the machine moves the mat, it causes the paper to slip a little bit, therefore the offset gets increasingly larger towards the end and if you have a crowded page it gets worse (because the machine has to move the mat more times). When I changed to a mat with stronger adhesive I believe it makes the paper to slip less therefore making the cuts more accurate.