Which of the following most correctly states about the rationale for using estimated (allocated) manufacturing overhead costs instead of actual ones in calculating the cost of goods manufactured (COGM) incurred during a given time period?

1 Because actual overhead costs incurred may not be available when COGM is measured.

2 Because manufacturing overhead costs are easy to track.

3 Because manufacturing overhead costs tend to be immaterial these days

4 Because using estimated manufacturing overhead costs is required by GAAP.