I admit my original reply did not address a single method of wiring an AFCI MWBC, so lets clear this up.
First, there is only one way to wire a MWBC AFCI. You cannot use other methods that are available to a GFCI or standard circuit. The limitation is due to the fact that there are no AFCI devices like a GFCI receptacle. Even if there was an AFCI device, you would have to enclose the wiring to the AFCI device in EMT. To the best of my knowledge, the only available type of protection available at this time is CB protection.
Therefore, the only way to utilize MWBC wiring is to purchase a 2-pole AFCI circuit breaker. That is, if one is available for your panel. To the best of my knowledge, there is no 2-pole AFCI available for a Square D panel (QO or Homeline). Murray makes one at about $90. CH used to make one for their panels, it was well over $100. Murray will fit in Homeline, but is not UL listed for the use and will [should] fail inspection.
So, if you have a Murray or CH panel, are willing to pay a premium for the CB and deal with the fact that a nuisance trip will disconnect two circuits, yes, MWBC will work.
I am not sure if that is what you were getting at, as your reply was sufficiently vague to avoid any real explanation. I concur, if you follow the electrical code, it will work.
There is no cost savings to running a MWBC for an AFCI, but you do get the disadvantage of both circuits disconnecting on a nuisance trip. Having been through this already, I speak from experience.
GA adopted the 2011 NEC and this room requires it.
I'm sorry I didn't get into the minutia, but sometimes the simple answer is good enough. Nothing like running 6 MWBC circuits and finding out you need $300 worth of circuit breakers after the GWB is up. Or that you have a QO panel and they aren't even available.