I have created conversion variable eVar16 that has allocation original value(First) and expire after purchase. Due to code issue in datalayer code, I was null value in eVar16, but after making the change in data layer code, that issue was solved. In sever call for particular page URL, data is populating properly, but still Null value is coming in Report.
Also, Page URL total is 19, but total value is around 200. Please let me know, the reason for the same.
The reason you still see null is because of the Allocation(Original value) you have set for evar16.
Suppose value "Null" got fired for a user before you corrected the code and that user has not made any purchase yet, so the value "Null" would still be persisting for that user and will keep on coming into the reports as soon as user visits the site.
Regarding the page URL value could you please let us know the metric you are looking at?
Using Allocation as Most recent would help you out here but here persistence will play it's role.
Null value keep on persisting for the users if no other values of this evar set for them when they visit the site again after the changes you make. Once they are set with new value of this evar, null will go away.