Software maintenance fees can really add up. But since maintenance revenue represents a recurring (and therefore highly-prized) income stream, vendors are often loathe to negotiate there. But that shouldn't stop you from asking. In this market, you should at least be able to get to a higher tier of maintenance for a lower published rate. But as an excellent CIO Magazine article (by way of Analysis Zone) points out, you need to be careful about clarifying just what you're buying. CMS vendors in particular have sometimes been less than scrupulous, e.g. labelling upgrades as "new software modules" uncovered by traditional maintenance agreements...
Check out the CIO Magazine article