I wondered about that myself, thinking it would have been easier just to do the 12 inch block as one. But it's been a long time since I did paper piecing so i thought maybe there was something new to learn.
Did you ever get an answer? I haven't done the paper piecing block. I just printed mine, I didn't increase anything, because the pattern pieces looked to be the correct size. At least the one inch square they sent as the scale measured one inch on what I printed.
DeLee, adding photos is not hard, but not very intuitive on this site. if you are typing in a comment block such as this, it's the 2nd icon, as you float over it it will say image. on the tool bar above the text box. just click on it and it will take you to a browse screen, find your picture on your computer and click OK.