Unscrew the lens 1 turn (to uncouple the aperture coupling) and adjust the stopdown metering to be accurate. I'm pretty sure this stopdown metering is only supposed to be accurate with old lenses.

Don't forget to keep the eyepiece covered when metering, the cells can see through there...

If you find that you can get it to work easily along this line of reasoning... Then I suspect that's what the balance control is for.