Well, throwing a cat in with these pigeons, the DA is actually derived from the DH and not the other way around. To be precise, the number in brackets is the absolute minima for a particular system at that location. In other words, a plain old vanilla Cat I ILS has a system minima of 200ft providing there are no funny obstacles in the relevant approach/climb-out segments.
So, we all sit there and fly to a system minima with this minima being converted to an altitude (normally handily done by the chart editor in annotating a figure outside the brackets) using the threshold elevation as the number to add on to the minima. We then add our various safety factors which are often prescribed in company ops manuals.
PS. Anyone adding a number to DA/DH in order that you don't descend below this figure on a go-around clearly doesn't understand procedure design and should hand the reigns to someone who does.