I think that $515 for a DOS software package that hasn't been updated in at least five years is a bit steep. Especially when you consider that for a while they posted it on their site for free. Some corporate bean counter must have decided to try to squeeze the last dime out of the product.
Side, I can tell you this. If you can find somebody who has the master floppies, there is no copy protection or registration required when you install it.