I didn't watch the video but from your wordings, I will try to put it this way.
Lets say that there is some data in this hierarchy:
1 Item1 45 GBP
2 Item2 32 GBO
3 Item3 27 GBP
When FileInput processes these three records, as there is code list error at line 2 for the currency, it will not process rest of the two records as well.
AND
FileInput doesn't have the capability to process A header record with multiple Items (unless you make some manual tweaks to the generated XML File which is not recommended).