Exactly, you have to default to fill or kill within the trading day. You just can’t treat certain products like a standard queue... sometimes time is the most important component
FYI, FillOrKill/ImmediateOrCancel are not the same as a day order.
FoK/IoC means “do not queue this order”. It’s immediately filled (or not) (or, for IoC, partially) based on whatever orders are already in the book, and then you’re done.
Whereas a day order is queued until the end of the day or until it’s filled, whichever comes first.
