Please do not assume that X1 is the one sending out these royalty demands. As I said earlier, X1 buys in viewer technology, ultimately from Oracle.
Other writers of file managers have stumbled across the cost of dealing with Stellent/Oracle/Avantstar.
Then again, Greg's numbers seem odd. X1 costs less than US$50, AUS$55.95, less than you have to pay for DOpus. QuickView Plus costs just US$49.00 to buy.
So Oracle must be doing the usual trick of hitting the "small guy", especially a foreign one, harder than it hits the industry's "giants".
Adding US$56 royalty per copy sold means that it would be cheaper to buy both X1 with DOpus or QuickView Plus than to buy QuickView enabled DOPus.
By the way, the "trial version" trick to get the viewers may well be of dubious legality.
On this trick, has anyone tried it with the trial version of QuickView Plus? This would have the advantage of not imposing on your system stuff that you do not intend to use.