Ok, was she feeding more frequently overall before sleeping through the past two nights? Just wonder if there's been a change.
I personally wouldn't be so worried about the longer break overnight, as with the low number of feeds overall. Do you think you could squeeze in an extra feed or two during the day, and maybe one during the night if she's going long stretches? I am loathe to mess with sleeping babies, but 6 feeds is quite low is all. It does sound like she may be ok at the moment - watch those nappies, though, you would want several poos per day generally, so if they drop off it might be a sign she needs a little more.
Not sure if this is helpful - have you called the ABA? 1800-686-2-686?