Our FCCS_Balance Sheet doesn't cast

Summary:

Having loaded our & consolidated the balances from FCCS into TRCS we are noticing an odd quirk when we look at the balance sheet in an ad-hoc grid.

Content (please ensure you mask any confidential information):

The FCCS_Balance Sheet is made of up of Net assets, which is the sum of all the asset balances less all the liabilities, and Equity. The balance on FCCS_Balance Sheet is not zero - unless the override accounts are added to the grid. An example is attached (test values). These override accounts are shared from the primary, FCCS_Balance Sheet hierarchy.

Why does the balance sheet only balance if the alternate hierarchies are included?