This is roughly how it works:
CME computes the ratio of trades and modifies/cancels in a product. If this ratio exceeds a limit, IB gets charged $2,000 for that day for that product regardless how many contracts we traded (it may be 0, 1, or a million).
As far as the trailing stops:
If simulated stop orders are used, you will not get charged. If native stop orders are used, you will.
CME computes the ratio of trades and modifies/cancels in a product. If this ratio exceeds a limit, IB gets charged $2,000 for that day for that product regardless how many contracts we traded (it may be 0, 1, or a million).
As far as the trailing stops:
If simulated stop orders are used, you will not get charged. If native stop orders are used, you will.