What a column in an export is for in the roll-up: a level (region, team, person, account), a dimension (product, date), the value, or nothing. A numeric amount cannot be a level; two columns cannot share a role.
Few distinct values with one per person is a team or region. Many distinct values, one per row, is the account. The map guesses; the person confirms; the identity checks.
Names, notes and addresses have no role in the arithmetic and stay in the building.
Each column in an upload is assigned one role: a level in the hierarchy, a dimension, a measure, a date or an identifier. A person confirms the proposed assignment, and it is saved for the next upload of the same export.
An export has Region, Team, Rep, Account, Product Group, Invoice Date, Net Amount and Account ID. The first four are levels, product group a dimension, invoice date the date, net amount the measure, account ID the identifier.
Two columns both assigned as the measure, such as gross and net amount, or a name used as the identifier. Totals double, or one customer becomes three.