User blog comment:B1mb0w/Deeply Nested Ackermann/@comment-25337554-20150602100224/@comment-10262436-20150602102339

And you are correct on the other point as well. I have changed the Trailing zero rule to read:

DNA(x,y,z,0,0, ... ,0,-1) is substituted for DNA(x,y,z-1,z,z, ... ,z) in all cases

Thanks for spotting these :-)