Double action revolvers have a much longer and heavier pull than semi-auto pistols. This will affect how you need to place you finger on the trigger. For semi-autos that are DA/SA, the first pull should probably be done the same way. Pulling singel action triggers with your finger up to the first joint may cause you to pull right. If what you are currently doing works with what you are shooting, then stick with it. Just be ready to adapt if you switch guns.
The ATF should be a convenience store instead of a government agency!