How is your database structured with regards to the returns? Meaning, where does the return data get saved to? Do you have 9 fields somewhere in a table where you can store return info?
Might I suggest that if your data is structured that way, that instead you consider having a returns table that holds fields like this:
CustomerID
ReturnIncidentNumber
and have a table that stores return details:
ReturnIncidentNumber
SKU
ReturnDate
That way, you could just store the 1st SKU into the return details table. Then when the additional returns form comes up, make sure it has the same ReturnIncidentNumber as the 1st SKU, and just add it to the return details table.
This is the way most order systems are structured. They have a orders table, then an orders detail form.