Feeding question??

My daughter is 5.5 months old and currently has four 150ml bottles a day and three small solid feeds, What i am wondering is would it be ok to feed her three 250 ml bottles instead? She struggles to get through the 150 4 hourly but today she slept through her lunchtime feed and took 250 without a problem. Im just worried she wouldn't be feeding often enough. She will be getting more just less often...what do you think?