I'm not well versed in creating interfaces but is there a way a calculation can be introduced that would divide the unit cost by 10 for these few items and enter that result in Meditech? Otherwise, if you have to manipulate Lawson to get the cost per use you could create a lower uom called a "use", USE perhaps so you would have for instance
1 USE = 1 USE 1 EA = 10 USE 1 CA = 100 USE
Make USE a secondary transactional uom only and issue or purchase by the EA or CA. I can't think of any reason this wouldn't work. Might cause some headaches for inventory though if any of theses items are stock. There are many user fields that could be used to store that conversion value but I don't think the standard interface files grab any of those fields.