8 hours were added on wrong Project "A", timesheet is posted. Now this posted timesheet is adjusted.
User added 8 Hours on correct project "B", now for "A" he add 1 hour( Total hours 8+1 =9 hours) , now timesheet posted.
If we check "Posted Transaction review portlet" we get 3 records like below.
Proj - A +8Proj - A -7Proj - B +8
While adjustment he added 1 hours so 7 hours were removed from Proj "A".
If all the 8 Hours need to zero-out from Proj "A", then giving Zero or leaving empty will work after the timesheet gets posted for second time(while Adjustments).
If you are asking whether you can remove all the hours by setting the number to 0 the answer is yes.
If you are asking whether you can adjust a timesheet more than once the answer is also yes. There is no limit how many times you can adjust a times sheet. What you will be adjusting is the last posted adjusted timessheet. Like in your case the one which has 1 hour on project A.
Yes, if you want 8 hours to 0, you need to set 0 in adjustment timesheet.
If your PPM is old version (maybe 12.x ), you may be able to remove timesheet entry in adjustment timesheet.
If you remove timesheet entry, it does not mean 0 hours. It is not a correct operation to change it 0 hours.
I experienced that some user used to remove timesheet entry in adjustment timesheet to change actual hours to 0.
After post timesheet, actual hour will not be 0 hours. Previous hour is still remained.
If user wants to change it to 0 hours, user must set 0 hour in adjustment timesheet explicitly.
It often confused user.
The Delete button in adjustment timesheet is removed from 13.x version.
I think it is enhancement to avoid miss-operation.
Agree with that that in some versions removing or deleting the time entry record on an adjustment timesheet instead of setting the hours to zero created problems and should not be done.