6wo DD is ff, using a combination of powder and ready made milk. When I use ready made I fill the bottle to 5oz, which she usually finishes. When using powder I put 5oz water in and add the powder, increasing the total volume of liquid to about 6oz. If she then finishes this, has she had 5oz or 6oz? I'm not sure if I should be reading it as the amount of water+scoops I used or the total amount of milk once mixed 
I ff DS and generally went by the amount of water, but never paid much attention to what he drank as it didn't seem excessive. DD seems to be forever feeding!