With limit orders available, it would also be great to allow portions of limit orders to be filled if there isn’t enough volume for the full limit order.
There shouldn’t be any added complexity regarding commissions per trade as e.g. 10% of zero is still zero :). I would expect the same for USD FX fees as these are just a % of the filled transaction.
Partial fill is a standard trade execution on stock exchanges. FT could pass the orders to stock exchanges to enable partial fill.
It’s better to let stock exchanges handle and execute orders so that FT don’t need to reinvent the wheel. Placing limit orders on exchanges also adds liquidity. There’s a feature request for exchange executed orders [Feature Request] Allow limit orders to be placed on stock exchanges