We were told that our baby needs 28-32oz per 24 hour period, and some babies need 24-32oz, so if she’s getting at least 24oz and your pediatrician & lactation consultant aren’t concerned, then you’re good! Since I’m ebf, I make sure he’s getting 8-10 feeds in, but I also assess his sleep, disposition, & diaper output to gauge how he’s doing.
Could be a growth spurt. My son eats 6 oz every 4 hrs but usually has 1 bottle during the day where he only eats 5 so he eats again in 3 hrs and then his bed time bottle was 6 until he decided he wanted 8