I think there are much more potential drawbacks, then just “Slight latency penalty”

If our proxies consist of more than few rows, then our system become much more complex and will...

@Phil Parkin

>  Have you tested this script for performance with, say, one million rows in the Excel sheet?

I just cannot imagine an Excel worksheet with one million rows. In our...

Sorry, what is the point to create a SSIS script AND C# code?

Isn't simpler to create just small C# program or even VBA script  with the same functionality ?