Cumulative power limitation

It does allow it in Dashboard 2.0 (I shared doc link above)

You may need to update version to 1.12.0 (released today)

I think you are looking at the problem incorrectly. I think your 100% mark should be at 1166 each. Then when you drag the one slider above 100% it starts lowering the other two proportionally. So the max on each would be 128% not 100%. No user wants to be told they can’t do something! Just let them do it and take the consequences.