ListView and Duration

[ntaryl]

Good  afternoon 
I work in a small example with a listbiew.Want every time when a  new item come in the listView then start a duration time  .
In google find  a nice function for the duration  time  and  try to make a small  example  .When start with the first Item everything  is  ok  but  when  put  another  not  start from Zero but  take the same time from the  first   
someone  can help  me 
Thanks for the time
attach  the  code 

[ntaryl]

Thanks   
the Question  solved 
credits  to Martinz