loading multi-column Numeric data as amount

Summary:

loading multi-column Numeric data as amount

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We have a source file with a receipt and payment column that we need to load into one amount column in ARCS Transaction Matching. The file has a header row. We tried setting up the file as Multi-column - Numeric Data type in the Import Format. When executing the data load integration, the process fails with errors. Do I use the Expression Type 'Column=start,end' or 'Driver' when I have a header row?

For example, when receipt column has 1000.00, the payment column has 0.00 and vice versa.