Called customer support but they would not adjust the price to fit the short term of the added licenses. This software was inefficient and hard to use so I canceled it 2 years ago and replaced it with Avast, which is excellent.
Trend Micro charged my bank card without any notification a month ago.
Trend Micro has released a new pattern to correct this (pattern 943):
Microsoft has formally announced Windows XP (April 8, 2014) and Windows Vista (April 11, 2017) end of support.
Because Microsoft no longer fixes issues on Windows XP and Windows Vista, it has become increasingly difficult for Trend Micro to keep users safe on these operating systems.
When adding additional licenses on Trend Micro they will charge the full term cost, but short term end your new added licenses to the expiration date of your previous licenses.
They only show the short term end date of the added licenses after payment and check out.
We encourage all of our users to upgrade their PCs to a more modern operating system which will provide greater stability and security.