Thanks for your email, you have a whole team 24/7 in the forum that can answer your question. I can try to get to your emails when I can.
The way our out of the box runs reports is that it has stored procedures that pull the data. The reports simply reference the stored procedure(s) through datasets.
You may want to go through the report through Report Builder and see which data set represents the table you are looking to tweak. Open the dataset and see which stored procedure it references and you can open the stored procedure in SSMS and tweak then refresh the dataset in Report Builder for that stored procedure. You should see the new field.