The printed output from the LaserWriter 8500 is within specifications and is not a cause for concern for the majority of customers. If you require precision output, Apple has released a modified PPD file which provides a method for fine-tuning the printed output. The PPD provides 8 adjustment settings from which to choose until appropriate output is realized.
The modified PPD file titled LaserWriter 8500 PPD 1.2 can be downloaded from the Apple Software Updates web site at http://www.apple.com/swupdates. A Read Me file is included with the update which provides detailed installation and usage instructions.