Question on Yanfly's Absorption Barrier for a custom formula

[SWShredder]

What I want to do is pretty simple. I want to make it so the flat Barrier penetration is dynamic with the damage. Low damage doesn't penetrate while higher damage skill penetrate more. I just can't seem to find what to put in there for it to calculate the damage done. I tried the following and a lot of variant but it doesn't do anything.


<Custom Barrier Penetration Flat>


flat = damage^2 / target.mhp


</Custom Barrier Penetration Flat>


So if anybody could chime in and tell me what to put in there for it to works, it would be very appreciated. Thanks.