That’s correct - no one should fill above the circ scar line regardless of the type of filler. That to say you’ll be surprised how a good technician can taper the filler so that the outcome is decent. Mine is high as well and I have very little issues with it . Also loose so the worst possible combination yet I’m overall pretty pleased with the outcome.
Idk if it's that they can't. I think maybe and I'm just guessing it may be for aesthetic reasons. The circ scar will be tight and you'll have a noticeable indention instead of a more natural tapered look. I've had 2 rounds of Ellanse and after the first one there was an indention where my scar was but after the 2nd round to taper it you don't notice it at all