You do not state whether your order was a buy or sell
It doesn't matter as the principle works both ways
Let's say it was a buy order
Therefore someone placed a sell order that cleared all the orders ahead of you bar 165 shares; hence you got 165 shares of the 100,000 you ordered
The balance of your order is now top of buy queue
However, as you made your order 'good for day' the order was then purged
If you had left your order open ie not made it good for day, then it would have been top of the buy queue for tomorrow
So, yes, you have just paid the minimum brokerage of $10 for $20.625 worth of shares
As a PS
If you had let your order expire in the standard 28 days there are a couple of scenarios
I - your order would be first in the queue for the next day and if then the balance was fill you would only get charged the balance of any brokerage owing; in your case the balance of the order is worth around $12,480 so you would probably be charged $9.95 brokerage meaning a total of $19.95 on your total value of $12,500
2 - if your order was not looking like getting filled the next morning, you can go in and amend the remaining order value to ensure the balance of your order is filled
I NEVER do 'for day only' orders for exactly the reason you have experienced in your example
I always do the 28 days and then, if my order is only partly filled, I can review the next morning having looked at the other buy and sell orders
If you get to day 27 and you order has still not been filled, you can go in and amend the order expiry date for another 28 days
Yes; it is frustrating to pay $10 for a $20 trade but that is the way it works; noone can force someone to buy/sell shares so that your order is filled
