Pre-order management App: Auto-release and Order Splitting

In the case of Pre-orders, What happens when merchandisers auto-release orders and keep order splitting on?

Similarly, what happens when order splitting is off.

In case of auto-release, when order splitting is ON, a pre-order item will move to the pre-order parking and in-stock item will directly go to the brokering queue.

When order splitting is OFF and a merchant has opted for auto-release, then again, the in-stock item would go to brokering queue for fulfillment. Auto-release would only check the promise date and inventory of an item, therefore, even if splitting is disabled, a part of an order that is in-stock would be shipped and the pre-order item would stay in pre-order parking.