Hack to Upload Multiple Invoices to Same Customer Using Google Sheets Add-on
When using the Google Sheets Add-on to upload invoices, trying to upload multiple invoices to the same customer can produce the error "WARNING: The following field(s) have inconsistent data on different lines: Invoice Number. The first value in each field will be used."
This happens because Wave generates a new invoice when it detects a new customer in the Customer Name column but not when it detects a new invoice. Thus, Wave combines all contiguous lines for the same customer into a single invoice.
Hack to upload multiple invoices to the same customer:
Separate each new invoice with a blank row. Wave will detect the blank row as "new customer" without uploading a new invoice. Then, start a new invoice on the next row even if it is the same customer.