I bought a new Olfa ergo 45mm cutter last night, plus a pinking blade, which I put on the new cutter. Dug out some scraps to see how it worked, and it was terrible, took several cuts, mangled the heck out of the scraps. Went on-line today to try to figure out what was wrong, and on the Olfa website, there is a video and a pdf on how to replace blades. When you put on one of the decorative blades, like the pinking one, the round yellow spacer gets switched to the side with the blade. I didn't see anything on the package that said to do it this way, but it was late at night and my eyes aren't the greatest. Haven't tried it yet, but will tonight when I get home, and let everyone know how it works.
Here is link to the PDF, which shows how to change both a regular blade and a decorative blade.