Its not quite that easy. Take immigrants to, say, Southern Rhodesia. A person born and raised in Kent, England who died in Cape Province, South Africa, but lived his entire life in two provinces in Southern Rhodesia. He migrated from a port in Southampton, Hampshire to Cape Town, Cape Province (which is clear on the ship's passenger list), but transition between birth county and eventual African residence is not so clear cut (or necessarily well sourced).
The migration categories are far too complex. I suspect many profile managers may struggle with this series of categories. The question that was raised in my mind: is it necessary to drill down county/province (called the admin entity) of origin to county/province of destination and what is the pertinent variable or parameter (birth/death or port of exit versus port of entry - and there are others, like known residence post migration)? Surely we should simply satisfy ourselves with, in this case, a man of Kent migrating to Southern Rhodesia.