Multiple Critical Strike Upgrade *need Help*

Multiple Critical Strike Upgrade *need Help*

Ok, so i am creating an upgrade that will have three levels of critical strike. I made the upgrade, then made the ability giving it the requirment of the upgrade. I then gave the unit the ability. I upgrade critical strike, and it works perfectly on the unit.

Now that i gave you background on what i have done, here is my problem. I want the upgrade to have 3 levels. I can't seem to figure out how to do this though. It will only keep the level 1 ability.

-Thanks in advanced.

Although i cant answer this question directly, maybe you should look at the 'better wardrums' upgrade and see how that works to improve the % bonus.

Can anyone help me?