Hi Syeda Tahoora,
If the project is complete, you may request the client to close the contract. That way, the system will automatically request the client to share feedback. This help article gives a detailed overview of how JSS is calculated and what may cause changes in the score when it updates. I also encourage you to check this announcement with information about the recent update to JSS calculation. Because we are now weighing jobs with higher earnings more, if you received less than stellar feedback on one of those jobs it may affect your Job Success Score more.
The Upwork system takes snapshots of your six-, 12- and 24-month history in the marketplace and calculates a score for each. The best score out of these moving time windows is displayed on your profile and updated about every two weeks. If the contracts that you are referring to are still within the 24-month window, then this should be included in your JSS calculation.
We determined it was most fair to apply this new calculation to all freelancers at the same time rather than having some freelancers under the old calculation and some under the new one. By doing it this way, clients can also trust the Job Success Score they see for all freelancers is calculated the same, regardless of whether a freelancer has new or only older feedback.