Uh? Not even close?
Injector offset is the amount of time for injectors to pass the transtional stage. Otherwords injector closed-to full open amount of time this takes. This is usually set up by a mfg. for a specific application at a general voltage & a specific fuel pressure. Then a pcm has a better understanding of true seqential fuel injection & getting fuel there in right time & quantity especialy at high rpm.
ifr vs map is that whatever you are referring to, and that is typically just known as the IFR table.. Not the offset table.
Offset is Voltage vs millisecond.