I'm doing just 5 feeds a day: 7 (wu, bf), 11 (pumping - he takes a bottle), 3:30 (pumping, usually only get a let down on one side, he takes a bottle), 6:30/7 (bf), plus a df at 10:30 (bf), and my supply has been pretty good (on weekends I nurse at all these times, usually only on one side each time).
My last two babies I did see a slow down in supply at around 6 months, and I've put that down to needing to replace parts of my pump since it wasn't suctioning well. However, with my first I was pg at 6 months (while ebf/ebm), so that probably caused the supply problems then, and for my second I got af at around 6 months, so with my pump needing replacement parts my supply did drop then (but I was still able to nurse and pump for her for another 1.5 months when I became pg again and my supply dropped even further, she had never been a big drinker though in general). This baby is my first lo where my supply isn't dropping at this 6 month stage, and he's bigger (and better eater) than my others.
I think that as long as you are offering her feeds and she is nursing most of the time with you (at least 4 times per day at 7 months) you should be ok and your body will just adjust to what she wants. In the early days your body is getting used to producing milk, but now your body knows all about it, so it works accordingly. I would just try to pump when your lo is taking only a bottle in order to stimulate the feeds that she would be taking (except at night I wouldn't pump
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Also DD never took too much milk in her bottles (she never had more than 4 oz) and was able to go 4+ hours between bottles, especially at 7 months. I noticed she preferred more solids so I gave her a lot of that, over her milk intake, and just upped her yogurt and cheese intake too to compensate. I'm just mentioning this to let you know that although I often hear about babies taking 7-10 oz per bottle and it seemed like my LO should've been starving based on how little she was taking, really she was fine and I didn't have to worry too much about it. At this age, all you can do is offer some opportunities to bf, and the rest is up to her.