Is she drinking enough?

Katie

My daughter is nearly 4 months but is only drinking 4 7oz bottles a day. She sleeps through from 8.30 till around 7.30 and has a bottle every 4 hours. On her formula box it says she should be having 5... she was having 5 5oz then started sleeping through so went down to 4 but has upped the amount she drinks.

Just wondering if she is eating enough?