Maxperson
Morkus from Orkus
No more than you are making up details on the volume of the liquid. And your way has to assume that the entire world consists of morons who put valuable magical healing potions that save lives in thin containers that would shatter if an adventurer stepped wrong. I hope you roll saves for all of those potions every combat, because they aren't likely to survive one in a container that thin.But this are way more assumptions and making up details where there are none.
You also have to assume that every potion EXCEPT healing is typically 1 ounce of liquid for some reason. A very rare 2500gp Oil of Sharpness? 1 ounce! A common 50gp Potion of Healing? 15 ounces. A legendary 25000gp Potion of Storm Giant Strength? 1 ounce! A common 50gp Potion of Healing? 15 ounces.
Your assumptions make no sense. Neither balance nor rarity account for why a Potion of Healing weighs so much more than every other potion out there.