Do you have feedback on your design?
If you don't have feedback for controlling switch then you don't hope that your output will be stable (it is depended to it's power, if you consume high current your voltage drop P=V*I).
Also I think it will be dependent to your device specifications.
If you had feedback then it try to modify and correct your output however as you know, each component has a definite characteristics such as your switch (IGBT or MOSFET) and transformer
So if you have a correct design then it will work good and you don't have drop voltage.
Best regard