And remember that the IRS is not one single ride at a country fair with one processing line ... they are more like Disneyland with multiple rides with different line wait times. At each of the IRS processing centers they have different departments that process returns at different rates and within those departments the individual employees will also process their stack of work at different rates. So although the IRS tries to process things in the order they arrive it is just not that simple. Due to staffing issues they were even shuffling cases of paperwork between processing centers to even out the work load.
