Autologout only checks activity for the last 17 seconds

I was thinking that this module was reseting the sessions everytime there was any input on any form. But I have discovered that only checks if the sessions is active if there is an input when there is less than 17 sec left.

Example:
01:59 log off time > Activity at 01:00 > 00:17 checks if there is activity > 00:00 pop up to reset the session > end of session
01:59 log off time > 00:17 checks if there is activity > activity at 00:10 > 00:00 restarts to 01:59