Try designing and using two hardened guides one on the inside of tube and one on outside of the tube. Why dont u try laser drilling or wire cutting if you are so particular and you need hole on either wall of tube. End mill will help you if you are still wanting to go for drilling process.
On rme1's suggestion is like asking the fabricator to prove that monkey is man. Both material might look alike but not the same. A333 has good property for low temp impact as already explained. But your case of 10 deg is not low temp.
What if youy think of changing the whole to A106. I think...
