What AutoHARP does in order to make the transition easier and the programming easier is that it simply takes the money you have and lowers it to the least common denominator. So yes, anything over the multiplier will get converted into Gold. Don't think of the money shown as what the character is carrying in his/her purse, it's just the currency amount. It might say 6 gold, but the character chould have 30 silver and 3 gold pieces. I suppose it might be worth setting up the money to "display" what the character has and have a converted number in the background. This could work. In any event, having it set up the way it is now was the least stressful solution to another-wise head banging problem.
The only problem with this is taking your idea further. What happens if I have an item that is .2 of silver. Where does the change go?
This is something else worth noting when you make changes to the money system. You have to take into account that all the items are priced according to the Harp Fantasy system itself as a default. So if you are going to remove the Bronze and copper coins, then you should probably make sure that you change any item that is a fraction of a silver coin as to not make change that doesn't exist. In the end, it might be easier to just have your coins as an item on your character sheet that the player just has to keep track of.
Currently there are no XSD files for the XML files. I can create them. Perhaps I can have them available for version 1.0.2 which will get released when I have Martial Law finished. I think somewhere online there is an xml->xsd conversion program. That might be a short term fix.
One thing I think is important. I created AutoHARP to be very open and I definitely encourage the idea of customizing the databases. Just a few things to note: 1) realize that you need to backup your changes and keep track of what you changed. When you update AutoHARP and install new database updates, any information you changed in files that are a part of this update get overwritten. This is why I wanted to make it possible for people to create their own books and therefore get outside the generated files when making changes. 2) Some things might not be possible for a customization. Some compromises might have to be made.