Hi AJQ
Sorry to see that no one has offered assistance with your query.
If this is still outstanding the Job Profit and Loss shows all transactions associated with for an account with a certain job attached. The Profit and Loss report shows all transactions associated with an account regardless of whether it has a job or not or the actual job.
If you have narrowed it down to an account that is different you would be looking at running the General ledger detail report for that account to ensure that all transactions have a job and that the job is the same job you are using on that Job Profit and Loss report.