^Absolutely, Sol, it is a geometric fact that many seek to ignore with "looks like" arguments. I know I have used many photographs, using certain known or approximated objects of size, and used different shape calculators to try to get educated guesses as to volumes; they usually come close to what Foxy reports, but suggest that Beshine's volumes are more than others want to hear, which is why I have done it many times. While there is certainly a spread of results, they always exceed what others want to believe, and to be honest, often cause me to wonder if should could manage that weight as well as she appears to. In other words, I am often skeptical of my own results, however, Beshine's fitness it really outstanding, with muscles hard to ignore in her legs and abdominal area, the areas most needed to handle heavy weight on the chest (it is only back if she hadn't employed such swayback posture).
Mary provides visual proof of her expansion by wearing the same dress and as I pointed out, it no longer can contain her sideboobs, which is indicative of how much larger her boobs actually are, yet, as you point out, they are not yet double in size. It is the same game I have played on the Beshine thread when asking what percentage larger comparison photos look; once you commit to a percentage, you may not like the result of the mathematics. Essentially, as the size increases, to notice even a slight difference requires a exponentially increasing amount of volume. And as we have seen in the history of the thread, fills always result in an immediate change in the feeling of weight, however, that feeling dissipates over the following few weeks as she becomes stronger and acclimated to the new weight.
Mary keeps working out; already extremely toned, while I'm sure she initially feels the slight difference, within days, she probably has gotten used to it. I'm also quite certain her low BMI makes sizeable fill-ups difficult, a trade-off for the body she loves and the body she desires. There is little doubt that she will have very little difficulty with the increasing weight of her boobs, however, as her boobs increase in size, many of the things she is able to do now, may become increasing difficult, purely because of how her boobs interfere with normal movements. It is my hope that Mary loves and appreciates all the adaptions she will have to make because of boobie size.