When you get into the realm of enterprise sales you have to find a way to predict a fixed top-end price and it has to fit into their perceived value of your product even if they use less of the service than you or they predict. An enterprise customer will tolerate a higher per-unit cost for the assurance that they won't experience cost overruns. This is because they're budgeting large line items once a year and they can not overrun. This would mean that you'd price the product at 12000 euros per year and hopefully the value of the product is still high enough to justify this in their minds.