it say in it tool tip that the amount of attack damg done to a unit does 60% around it.

Ok im fine with it but one problem it does not proc crits. AS Gangplank i witness 690 damg to a golem unit to his buddy only did 162 damg through out it hasnt gone up.

Here my question is it base off of ur base total damg or the damg done to that one unit. cuz you have effectively made it useless if it doesnt apply crit damg in it.

It does not apply Crit, just your normal attack damage and that does not make it useless, it would be far too strong on some champs if it applied crit.