Need help please!

Hi, I just started using d3helper and I like it. But I have one problem, I don't know how to get my bombardment to be used on COE. Currently my iron skin procs when physical COE is up (I would like it to proc 1-2 seconds before PHYS COE, any suggestion there?) but my bombardment is being used at the last second on iron skin, which results in him doing bombardment when fire COE is up and not phys.. How do I fix this problem please?