Lets look at two tables from level 2 (wards): MG201 (Age and sex) and MG203 (Ethnicity). The interior cells in each of these tables will be subject to different SCAM runs.
Cell 1 in each of these tables contains the flows of total migrants between 10,608 wards in the UK and 9,432 wards in England, Wales and Northern Ireland. These totals are aggregations of flows in interior cells
The question we can ask in this case is: What differences occur in non-zero ward to ward flow totals between the two tables?