The MT4 User Interfaces (UIs) operate primarily as a front-end system intended for user convenience, facilitating order placement and chart viewing. OANDA endeavours to mirror the v20 account in the linked account in MT4 to the best extent possible, but it is critical to note that the definitive system of record and the ultimate source for Order Monitoring and Execution, Marked to Market Open Positions, Margin Utilisation, and Margin Close-Out processes is the v20 account (accessible via the proprietary OANDA UIs); it is not the MT4 account that is linked to the v20 account.
Download the OAP sub-accounts-notable-differences 2024-09-16-V4 file to see the notable differences between the various sub-accounts.