We improved the way we are pushing data to Salesforce via the UPDATE command. Once a multi match is found you can choose which record/records you can update.
First - The first record matched based on the Salesforce system field CreatedDate (Ascending sort order).
Last - The first record matched based on the Salesforce system field CreatedDate (Descending sort order).
All - 200 records.
Skip - Do not update at all.
Create - Create a new record.
Enjoy!