you can choose to not print the instructions on the USPS site as well. it is a pretty hard to find tiny tiny box that is hidden among all the other crap you have to click on but it will disable that half of the label. you have to click it every time though and I tend to forget half the time. on copier paper it is no big deal but I am one of those that feels it when I waste a 6 cent label.
look for the box on the page where you pay and print. it is left and a little above the pay button.
says something like print without instructions or something like that. you know that insiders lingo the rest of us just have to scratch our heads about.