Hi Kamlesh,
In addition to the above replies here is one more example for shift factor late completion
Your Plan date is 01/10/2013 and Completion date or Techo date is 10/10/2013
If Shift factor is 100% then next planned date will be 10/11/2013
If Shift factor is 50 % next planned date will be 05/11/2013 (taking 50% of difference days of planned and completion)
If Shift factor is 0% next planned date will be 01/11/2013
Best Regards
Kalyan