Good question, @cgoneal. The way that accounts are named in the Amazon CSV export is different than the names used for accounts in Tiller Money spreadsheets.
The Tiller Money Labs Import CSV Line Items workflow does not currently try to reconcile the names provided between the two data sources— Tiller Money Feeds and the line-item importer.
If you compare the Account-column content for Amazon line-items, you should see that the transactions match up to what was in the CSV’s Payment Instrument Type column. If not, let me know. 
Randy