Decompensated cirrhosis is where the liver is damaged enough that it can no longer do its
jobs effectively. On of the livers
jobs is to remove
ammonia. So like I said as far as I know having high levels of ammonia causing is by definition a symptom of decompensated cirrhosis.
However, the liver can improve with time by eliminating the cause of damage. So you could maybe have slipped into decompensated cirrhosis then stopped drinking and returned to being compensated when the HE improved.