The Allocations module provides different methodologies to both calculate the basis of the allocation (the amount to be allocated) and how the basis is allocated. The basis is allocated to designated Budget Account/s (the "Destination Account/s"). To designate a Budget Account as a Destination Account, it needs to be checked as "AllocAcct". The allocation of the basis is always offset by an equal and opposite amount so that the Allocation results in a net zero impact on the Budget overall. The opposite amount is allocated to the "ContraAlloc" Budget Account.
When the "ContraAlloc" checkbox is checked on the Manage Objects it automatically checks the "ContraAlloc" box on the Manage Budget Accounts for all Accounts numbers that include the Object code. If you do not want a particular Budget Account number to be subject to contra-allocation, it can be unchecked on Manage Budget Accounts. Similarly is you only want one Budget Account to be contra-allocated, it can be checked on Manage Budget Accounts and left unchecked on Manage Objects.
As changes made on Manage Objects automatically update Manage Budget Accounts, it is best practice to keep checkboxes on both screens in synch.
When the "ContraAlloc" checkbox is checked it creates the Allocation Sub-tab on the Account Details Tab. The data in this Sub-tab populates from the Allocation module when the Budget Account Number is used there.
In the below example $248,822 was allocated to the "Destination Account" using the OrgUnits - Fixed allocation. The name of the allocation is "Test".
And below is the equal and opposite amount been contra-allocated to the "ContraAlloc" Budget Account: