Seems about right. There is no need to be anywhere near as restrictive as IB is being, to comply with the CME fee/policy. There must be some other reason to be so restrictive. IB's own trading could be one reason. Or, perhaps they are applying some other standard to a few large/institutional...
Sounds that way to me. Also, seems like a simple way to game IB's fees, at least if you trade more than 1 lots normally. Just break up your order into a few pieces when ever you need more credits.
Looks like IB's fees will primarily affect retail customers. The fees are per trade or per order, not per contract. So, it will hit small orders much more severely than large orders. A 600 contract order won't really care about a few $1's here and there. A one lot trader will.