How many days remaining from expiry date? From my experience, once you activate the license on first computer the license will start counting. That means you will need to install on 2nd and 3rd pc within one month to get maximum 365 days on each computers.

they according to ur 1st computer that install KIS and finish verifying key
example,computer A install last month and left 330days
and another 2 computer install after it,they also follow the same expiry date that computer A left
hope u understand

other 2 computer will follow the same expiry date than 1st computer install the KIS and activate it
let say 1st computer u use it 1month,and left 330days
and u install the KIS on the 2nd computer,and activate it
and the 2nd computer of KIS will also left 330days,not 1year ~~

conclusion,if wan install any kaspersky antivirus,install them in the same day if u purchase 3user de ~
because it expiry date will follow the 1st computer install ~~

This is so called extra period on the license.

As long as all the 3PCs enjoyed the full 1 year license, then it is good enough for your case.

What is the problem now?

The license count follows the activation on the first computer therefore explaining why your 3rd computer has left with 1XX days.
Okay, here is a simple example:

Computer A was activated on June 2010 while computer B was activated 6 months later which is on December 2010. Computer B won't get 365 days as computer A, instead it will only get 6 months. The license was activated on June 2010 and it will expires around June 2011. That means if you install the license on the 11th month, you will get 1 month of license.