Is she having enough milk????

My little one is 15 weeks on Friday and on Sunday I increased her milk from 6oz to 7oz as she was draining the bottles. The only thing is she only tends to take 4 bottles a day rather than 5 so she is having 28oz of milk in total, is this enough? Is there any way i could get her to take more??She was only taking 4 bottles when she was on her 6oz bottles as she dropped her night/early morning feed and that was her 5th bottle.

Any advice would be great, cheers.

Gem.xx