Look at the paper in your printer. A4 paper is 210 x 297 mm (8.27 x 11.69 in.) Standard paper in the U.S. is 8.5 x 11 in. I think (but i'm not sure) that RCPowers plans will have both an A4 option and an 8.5 x 11" option so depending on what paper your printer uses you can print either version.
EDIT: I looked at how I print plans and when I open the pdf and tell it to print (ctrl + p), I can select the paper size and then it places the tiles accordingly in the pdf. Not sure if that adresses the problem you're having but you should be able to select the paper size your printer uses when you print the pdf.
Thank you very much!