LoL Cannot Add Points To The Attack ?

So This is the think :

Attachment 7466

why i cannot add the points i have to the attack ?

build your physical a few then go attack as you have maxed attack

edit if that don`t work build defence a bit then back to attack

bcz the difference between highest and lowest should not exceed 20.. you reached a point where you have to give skills points to other skills first

one ability cannot be 20 points bigger than the other one