An assembly system may assemble articles of manufacture at a plurality of assembly regions and may log a time at which each article of manufacture enters or exits an assembly region. Assembly regions may include sequential assembly stations that process the articles. A method of determining when a specific article was processed by a specific assembly station may include receiving input identifying a specific article; receiving additional input identifying one of the plurality of sequential assembly stations; determining an offset of the identified sequential assembly station relative to a first assembly station or to a last assembly station within a region that comprises the identified sequential assembly station; and determining a time at which a second sequentially processed article entered or exited the region. The identified specific article and the second sequentially processed article may have been separated by a number of articles corresponding to the offset.