Is this normal?

My little girl is 8 and half months old and recently she has reduced her bottles down herself....

She has 3 meals a day and now has 3 bottles but she is starting to not be bothered about the middle bottle - I was doing 7 ounces in each bottle but then she wanted less in middle bottle as kept leaving some behind so I tried upping the morning and bedtime bottle and shes now leaving milk behind in the morning....

Is it normal to drop their bottles so much? She used to have like 4-5 bottles a day 🤷‍♀️

The health visitor said she should be having 21oz of formula a day but last few days it's only been 15-18oz