The 'Free and Fair' Enigma - Section 125(4) of CrPC

I'm thoroughly confused with section 125(4) of the Criminal Procedure Code (CrPC). It says that if the husband's whereabouts are unknown and he hasn't paid maintenance, the wife can file an FIR against him. But then, what's the point of 125(3)(b) which says that the wife's complaint should be sent to the magistrate who may then summon the husband for enquiry? Does this mean that the wife has to wait for the magistrate to summon the husband and then file an FIR later? Or is it a situation where the FIR is only necessary if the magistrate doesn't summon the husband? I'm thoroughly lost. Can someone please clarify this for me?