It is a good question. I have not seen anything in the qlik documentation about load order from QVC, as long its undocumented there is no guarantee in behaviour. However you could assume the data to be loaded as entered into the qvw.
If your order of data is important then you should order it explicit.
Plees ekskuse my Swenglish and or Norweglish spelling misstakes
AFAIK the order depends of the point of view - from the data-table or from the symbol-table. The data-table is always loaded with the order from the source - unless you apply an order by statement. From the point of view of the symbol-table respectively the (distinct) fieldvalues it's different because it depends on whether the field exists already.
If the field didn't exists the load-order is identically with the load-order of the data-table but if the field exists only new fieldvalues are added and the pointer increased to one bit and is stored in the data-table - otherwise it's just a lookup to fetch the right pointer value.
You may check this with some of your data and/or a few dummy-data by applying recno/rowno to your origin and deduced loadings and maybe even to your source-data (which may stored in a different order as they are displayed).