If I understand, I would make a new field in the script.
Load the data ordered by FormNum and Requested date;
when you have a row with the same FormNum as the previous (you can use peek) check the requested date of current row vs received date of previous row (you can use peek)
- requested > received --> new field is requested
- requested <= received --> new field is received +1
In chart, use received date and the new calculated field