I have to add that ip used by UTM devices are not counted. Some months ago I noticed that APxx ip addresses and interface addresses are not listed. I don't have any info about RED device.
Licensing for software ASG/UTM installs is based on IP count. Pretty much everything that goes through the ASG (uses it as a gateway) is counted.
Hardware is different as there are fixed prices for each tier of hardware but no IP limits. The unit's have suggested protected user counts which are based on testing of the specific platform's capabilities.