The way I remember this was the first generation AFCI only detected in the wall parallel faults. Then the next "combo" picked up cord parallel faults, then the next combo picked up series faults, but I am not sure those are actually out in general availability. The GFCI/AFCI combo (nothing more than a AFCI with 5ma GF protection instead of 30) is yet another thing and I think CH is the only one with it right now.
All of this does point out the mistake NFPA made in rushing these things into the code too soon. Now we have 2 generations of obsolete AFCIs installed that were put in at the point of a government "gun". How do you explain to your customer that to be really safe they should take out those old AFCIs you sold them as the best thing since sliced bread and put in the new improved ones. Do you really think they will believe you the next time you sell them something? I really think the manufacturers should be forced to swap out any old style with a new one for free since they were the ones who forced these things into the code a decade before they actually had one that did what they said they were going to do.
