IB does not offer this order type and IB conditional order does not have MOC as a selectable order type for conditional order (if it did that would be a workable alternative).
Have been requesting for years that they have this order type along with a creation of my own (maybe) The 'STOP relative order' where on triggering of stop price it places an IB relative order on the bid
Tradestation seems not to offer MOC order at all so can't even think how I could use Easylanguage to code this. In pseudocode: "IF Price > XX and TICKER = XXX Then MOC XXX shares" = Very clumsy would have to load a strategy for each individual ticker?
IB does not offer it because no exchange offers it.
MOC orders are sent to the exchanges, they are not simulated by IB. Therefore they cannot provide something like that because there are time limits when MOCs can be sent. What you're suggesting is something that participates in the auction as a stop order, can't be done (unless exchanges create a new order type).
Tradestation is no different, you cannot submit closing auction orders at the last second unless you're reducing imbalance.
Best you can do is a conditional order at 15:59:59 (or so) which is essentially just a stop order. IB will use ceiling if you don't use limit, so you can miss executions. Stop limit is your best choice.