The whole concept of fungible contracts is that in the proper ratio long and short positions net out to a zero position during the daily settlement process.
The CBOT literature on Dow Futures clearly specifies this:
Fungibility
CBOT mini-sized Dow ($5 multiplier) and CBOT DJIA futures ($10 multiplier) are fully fungible contracts. Fungibility allows the offset and liquidation of CBOT minisized Dow against CBOT DJIA futures held in the same account, contract month, and year in a ratio of 2 to 1.
Are you telling us that IB can't properly handle a simple fungible contracts offset during the settlement process?
The CBOT literature on Dow Futures clearly specifies this:
Fungibility
CBOT mini-sized Dow ($5 multiplier) and CBOT DJIA futures ($10 multiplier) are fully fungible contracts. Fungibility allows the offset and liquidation of CBOT minisized Dow against CBOT DJIA futures held in the same account, contract month, and year in a ratio of 2 to 1.
Are you telling us that IB can't properly handle a simple fungible contracts offset during the settlement process?