I thought it said (but I'll check again) that if there was a identical crossing then that would be the signal to take, but typically the oscillator would precede the MACD and so we would wait for a pull back and a second oscillator signal.
Right now we have a REALLY BIG pull back on the 30" chart for the NQ, but it might turn out to be a trend reversal. I don't think the markets like the pending bailout of the auto industry.