During a growth spurt you should feed on demand, otherwise your body won't adjust to a new demand and you won't produce enough milk for your baby. At what time you feed is a personal choice, so it is hard to say that it has to be 7 pm and 9 pm or some other time. I think that feeding two hourly during a growth spurt is a good idea if your lo is satisfied with that. As far as night wakings, they can be triggered by a growth spurt, if your baby is on a schedule during the day and doesn't get enough to satisfy hunger but it can be also related to other developmental things like learning to roll over, sit up or crawl, whatever happens at that time.
If she seems also hungry during the day, then definitely feed her more often, as soon as the gs is over she will be back to her normal feeding pattern. If she is only waking at night, this might be something else. My dd was waking every hour at 6 months because she learnt to roll to her tummy but was unable to get to her back on her own
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