Bottles/ounces

How did you decided your baby wanted more to eat? I’m debating on weather to add a ounce to my daughters bottles or not. The last time I thought she needed more I added a ounce and she ate it but would really seem uncaring afterward almost like she was to full. So then I bumped her back down, well here lately she’s been less and less content after eating. I’m worried to add another ounce just because what happened before but maybe she’s needing more...? FTM here