Great title! :)
Re bottle question on last thread, it's neither a good thing or a bad thing about the bottle being empty - it's more about challenging cultural practices associated with bottle feeding if that makes sense.
When we bottle feed, we know exactly how much they are having and that tends to act as a motivator for us to try and ensure they have their "usual amount". It can be a great source on anxiety if a baby is drinking more or less than they normally do. Whereas if we are breastfeeding, you can't stress about amounts in quite the same way as you have no access to this information. (Which can be stressful in itself... but that's a whole other topic!)
There is also a factor that when bottle feeding babies are not completely in control of the speed of delivery. Especially if they are lying down and the bottle is upended so that the whole teat is filled with milk (you may have been shown this to avoid them taking in air, as that used to be/still is commonly taught, although it's actually a myth) - sucking and swallowing is largely a reflex action and so it can be easy for a baby to take more than they need. Of course they will pull away if they really don't want it, but the threshold for "I have to actively keep sucking if I want more" and "I have to actively do something to stop this flow of milk" may be quite different.
So if you make your baby 7oz, and they get to 5oz and then decide they are done, it can be really tempting to go "come on, just a little bit more", tap the bottle, jiggle them, distract them, etc and hope they take more. In that scenario, an empty 7oz bottle wouldn't be great as you've just persuaded them to take 2oz more than they really wanted.
However let's say you know your baby normally takes 7oz, but you've read this advice and make up 8oz, then they stop naturally at 7. You end up with a wasted oz of milk, and formula isn't cheap. If you'd just made a 7oz bottle, they'd taken 7oz, been happy and not looked for more, nor did you do any persuading, then that empty 7oz bottle is a good thing as nothing is wasted!
So it isn't really a problem either way. And also, all of this stuff is really theoretical. It's just about looking at the (tiny) population level differences between breastfed babies and bottle fed babies and trying to see if any of those gaps can be closed not necessarily by the content of the milk, but also in the way that we actually feed babies. It's not something to really worry and stress over, it was just trying to give some context to the advice. I find context is helpful in deciding whether to follow some advice or ignore it.