Maybe that is the problem! Keep trying something different...?! If it drives you crazy, she must feel the same way?
Try to be consistent? 7 am,10 am, 1pm,4pm,7pm,9pm and 11pm. If she wakes up at 6, everything is forwarded with an hour: 6am, 9am,12pm,3pm,6pm,8pm and 10pm....falling asleep or not! Like I said, you can always make 9pm a dreamfeed as well...this SHOULD work, as long as you keep trying it consistently...Maybe it takes two days, maybe two weeks....but she will eventually get it, I am sure.
I started this routine when my son was 8 weeks old and he got the hang of it, within one week or a bit longer than that...with my help ofcourse, because I had to wake him up here and there to train his body to sleep according those hours. and he slept through the night with 8 weeks! The clusterfeeding was definetely doing it for him. and also good dayrests, cuz if they are not well rested in daytime it will make it harder for them to sleep at night peacefully as well.
As he grew bigger, I increased his intake on all bottles in order to leave out the 9pm one.
Keep trying!!