Umm. He did indeed say "one go". It seems pretty clear to me that he implied that the city was taken out in a single blow. Like a balefire nuclear missile.

I don't understand how you see "one go", and think that means hundreds of different "gos" over a longer period.

RJ said what he said, and I think this time you are the one making an unwarranted assumption.

I think there is enough circumstantial evidence for me to argue that there is indeed a way of modifying balefire and that Rand knowing how thanks to LTT, used a wide beam that was still weak enough not to cause massive damage to the pattern.