From Ombudsman report:
"It is the Ombudsman’s understanding that if field offices have a workload of 1,000 cases and USCIS determines each case usually takes one hour to complete, USCIS will provide financial support for 1,000 hours. Cases that take longer than an hour to complete are not provided additional resources in the office’s budget. Offices with more than the average numbers of difficult cases or offices that try to work the difficult cases thoroughly will not be adequately funded because the number of completions will be low. Meanwhile, offices that push to complete the easy cases will see their budgets grow. One field office visited by the Ombudsman has a large number of long-pending cases which require substantial adjudicator hours. However, officers at that office indicate that they cannot address the older, difficult cases without negatively affecting their productivity report to USCIS headquarters."