Hi Dmitry,
Thanks for the response. It seems the Kentico license page has changed overnight. According to the new license page, I still have 7 out of 10 available (two production sites, with one accidentally duplicated).
So it looks like I'm ok, as my IP-based address licenses for internal dev/test systems are not counted against the number of licenses.
IT had all internal computers using public IP addresses at one time and had two (144.xxx.xxx.xxx) but they were non-production (dev/test) websites; they are no longer listed in the license page. IT changed our internal IP addresses to private (10.xxx.xxx.xxx) range, so I thought when asking for new license, it would use up another license.
Thanks for the clarification.