This seems to happen with non standard paper sizes. Many different programs. If one uses a non-custom size it prints 100%

I have a customer with 10.9.2, CC Illustrator, even from a PDF, won't print 100%. They have an HP DesignJet 510 42" printer. He has to adjust his percentage to 112 to get 100. The latest driver is March 6 but that didn't fix it. In CS5 on a PC it printed fine, we just switched them from Windows to Mac on this work station. They're an all Mac shop now except for the server.

https://discussions.apple.com/thread/5514056?start=0&tstart=0

Just a heads up and a warning to anyone thinking of going to 10.9, seems like it's still a problem. Mountain Lion was fine from what I read.