The small details that nobody sees and unfortunately, are not always taught, always make the biggest difference, at all levels. And like the example you mentioned, you can now use that same concept in different positions to control posture easier
the marce is a term popularized by Jeff Glover and Bill Cooper to distinguish Marc Laimon's preferred entry of sliding in finishing on your hip with your lock "on top" as opposed to breaking them down and then finishing with your lock "on bottom." So the marce basically describes an angle change, and it can help people remember the different finish. The marce term isn't as popular as it was back in the day, but I think it's cool that some people still use it. There's also a farce if you hop over to land it on the far side, a mad-darce (stepping to mount to finish the darce), and a slarce where you grip your sleeve instead of your biceps if you're training gi. Those were the big Paragon Jiujitsu and Cobra Kai Jiujitsu names for the main darce entries and finishes back in the day.