I think you may be confusing an enterprise license with pricing based on processor power (PVU = Processor Value Unit). Current pricing TM1 pricing for standard installs is based on server plus named users. In the case of Entreprise TM1 the server price is calculated on the PVU basis, for Cognos Express is is a fixed amount. For larger companies you can then start talking about Enterprise licensing which may give you more flexibility, but starting at a higher cost. You amy also find issues where Ibm\Cognos sales reps dont really understand the TM1 model.
To be fair, the pricing has changed so frequently over the last 3 years that it is not easy to keep abreast with the current situation. Remember that, even before the Cognos takeover, Applix was trying to introduce named user licensing!