Alrighty, I'm going to suggest something that is a little bit last-resort but I think will give you and DD some consistency: set naps.
Basically, there are times that baby's biorhythms best suit sleep - around 9am and 2pm for most babies, so presuming starting the day at 6, that would work nicely with her A times and set BT at 6:30/7pm which is pretty reasonable, at least in my book. I think once you're offering naps consistently and not tweaking, you will be better able to see some patterns emerge. Also set times for naps and bedtime will help her self-regulate better with respect to sleep totals.
What do you think?