The check that every level of a roll-up sums to the same total: region equals teams equals people equals accounts. The single test that catches a member under two parents, a blank level or a mixed source, at the level where it happens.
total = Σ regions = Σ teams = Σ people = Σ accounts
Computed from one row-level file, it holds by construction. When it fails, the level where it first diverges says what went wrong.
Duplicate rows, which are consistent all the way down. The duplicate check is separate, and the reconciliation to finance is what exposes them.
The measure is summed at every level of the hierarchy and the totals compared. Region total must equal the sum of teams, of people and of accounts, and equal the control total.
Regions sum to $41.2 million, teams to $41.2 million and people to $40.6 million. Three accounts worth $0.6 million have no owner, which the assertion found before anyone saw a table.
Totals checked at the top only. Rows with a missing level drop out silently further down.