Frank Scavo of The Enterprise System Spectator has a great piece with advice to customers on managing high software maintenance fees. Money quotes:
If you are concerned about high software maintenance costs, there are several steps you can take to keep costs in line.
If
you have not yet purchased the system, understand that your negotiating
power will never be greater than before you sign on the dotted line.
Maintenance fees as a percent of the license cost are not cast in
stone. Everything is negotiable. For example, ask for a lower
percentage. Ask for maintenance fees to be based on the discounted
price of the software, not the list price. Ask for maintenance fees to
be locked in, not allowing the vendor to increase fees from year to
year.