How is Binance future order quantity calculated?

Question

I'm currently working with the Binance API and have encountered a scenario where I need some clarification on the calculation of the quantity in a specific order payload. Here are the details

Order Payload:

POST: https://www.binance.com/bapi/futures/v1/private/future/order/place-order
{
  "symbol": "LINKUSDT",
  "type": "LIMIT",
  "side": "SELL",
  "positionSide": "BOTH",
  "quantity": 22.31,
  "reduceOnly": false,
  "timeInForce": "GTC",
  "price": "13.456",
  "placeType": "order-form"
}

Market Information:

Current Price: $14.5
Available Quantity (avbl): ~161
Desired Cost: ~$40 or 24.8% of the available quantity

I would like to understand how the specific quantity of 22.31 was calculated in the context of the given market information. If anyone has experience with the Binance API or similar situations, I would greatly appreciate your insights into the calculation process.

Thank you for your help!