I've heard in the past this could be a problem but it didn't seem to be the case in the plans I had copied. I don't know how Kinkos did it - I dropped the original plan off, told them what I wanted and returned several hours later to pick them up.

The plan I had copied (one normal size plus one at 150%) was an old 1943 Cleveland plan. I was amazed at how perfect and clean the results were. The copies were "black line on white paper" so I assume this is not a "blue print" process.

One thing I was concerned about was that, because the old Cleveland kits contained "printwood" rather than die-cut parts, I had just copied the printwood sheets on a xerox copier set at 150% and I was afraid the parts would not match the plan I had copied by Kinkos because the copies (for printwood and plans) were being done on two different machines. But I checked and everything seems to match perfectly. If there is any variation or error, I don't think it would be enough to worry about as far as building goes. In my case it's not a scale model (the plan is Cleveland's 7 foot Super Condor sailplane) so that's not a concern.