Fees for customers within Germany do not include, and are subject to Mehrwertsteuer (German VAT). For customers outside Germany the appropriate
international tax treaties are applicable.  For the discount level On Demand the desired credits are not paid in advance, rather they are booked to the customer's account and invoiced later according to the actual support time used. Invoices are generally issued quarterly.  For the discount levels Basic through Bronze the customer
purchases a certain number of credits in advance. These credits can be redeemed immediately from the start of the contract time and are
valid for twelve months. Additional credits may be purchased at the same price as required.  On-site support incurs extra charges (travel, other expenses)
which will be explained in advance. Additional costs can be separately invoiced or calculated as credits as desired by the customer.