I've seen a lot of AquaHot service articles mention checking to see if the combustion chamber is warped but I haven't found anything definitive on the amount of warp. Per these pics, the diameter at the seam is about 4" and short diameter is about 3 3/4". Is there more life in it as is? If not as it is now, will "re-rounding" it by gentle taps with a rubber mallet...