This is how I look at it. To the fish DST and ST dont exist. The sun comes up when it does and goes down when it does and since most of our fish are from the tropics region thats fairly standard every day unlike those of us in the northern or southern hemispherse away from the equator. We have different amounts of day/night period thru the year where as the tropics is very close to the same amount of light/dark year round.
Now if personally you have your timmers set to turn on at a specific time so they turn off at a set time and you might want that time to be just prior to or just after you yourself turns in on a regular basis than you might wish to change the timming somewhat but by no means do you need to.