If the head of your school or teachers get angry or offended by you using something they don't know, you need to get the **** out of that school. They are dinosaurs that aren't interested in advancing grappling and BJJ. They are stuck in their ways and you will not be learning things to make you the best grappler possible.
If you've never heard of or seen someone at your school mention something about "the old way" of doing a sweep or technique, they've probably been doing it for as long as the school has been around. And guess what, those kinds of guys get smashed in tournaments. Not to say there aren't some things that never change and probably won't ever change, there are plenty. I'm only saying that if the system that's being taught has been the same for the last 10 or 20 years, it's old and you are probably doing things guys at other school would laugh at because they've learned very successful counters and reactions.
Btw I may be a little biased. IronMan's reply is probably better and more worthwhile.
Think. It Ain't Illegal Yet
"Discipline Hurts Less Than Regret"